Главная Обзор Помощь
Вход
xiaoguang_li
/
hue
1
0
Ответвить 0
Файлы Задачи 0 Запросы на слияние 0 Вики
Дерево: b788dfd07c
Ветки Метки
hue
/
ext
/
thirdparty
/
js
/
protovis
/
jsdoc
/
symbols
/
src
/
data_LinearScale.js.html

data_LinearScale.js.html 47 KB
История Исходник

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303 
  1. <html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"> <style>
    2. 

  2. 	.KEYW {color: #933;}
    3. 

  3. 	.COMM {color: #bbb; font-style: italic;}
    4. 

  4. 	.NUMB {color: #393;}
    5. 

  5. 	.STRN {color: #393;}
    6. 

  6. 	.REGX {color: #339;}
    7. 

  7. 	.line {border-right: 1px dotted #666; color: #666; font-style: normal;}
    8. 

  8. 	</style></head><body><pre><span class='line'>  1</span> <span class="COMM">/**
    9. 

  9. <span class='line'>  2</span>  * Returns a linear scale for the specified domain. The arguments to this
    10. 

  10. <span class='line'>  3</span>  * constructor are optional, and equivalent to calling {@link #domain}.
    11. 

  11. <span class='line'>  4</span>  *
    12. 

  12. <span class='line'>  5</span>  * @class Represents a linear scale. &lt;style
    13. 

  13. <span class='line'>  6</span>  * type="text/css">sub{line-height:0}&lt;/style> &lt;img src="../linear.png"
    14. 

  14. <span class='line'>  7</span>  * width="180" height="175" align="right"> Most commonly, a linear scale
    15. 

  15. <span class='line'>  8</span>  * represents a 1-dimensional linear transformation from a numeric domain of
    16. 

  16. <span class='line'>  9</span>  * input data [&lt;i>d&lt;sub>0&lt;/sub>&lt;/i>, &lt;i>d&lt;sub>1&lt;/sub>&lt;/i>] to a numeric range of
    17. 

  17. <span class='line'> 10</span>  * pixels [&lt;i>r&lt;sub>0&lt;/sub>&lt;/i>, &lt;i>r&lt;sub>1&lt;/sub>&lt;/i>]. The equation for such a
    18. 

  18. <span class='line'> 11</span>  * scale is:
    19. 

  19. <span class='line'> 12</span>  *
    20. 

  20. <span class='line'> 13</span>  * &lt;blockquote>&lt;i>f(x) = (x - d&lt;sub>0&lt;/sub>) / (d&lt;sub>1&lt;/sub> - d&lt;sub>0&lt;/sub>) *
    21. 

  21. <span class='line'> 14</span>  * (r&lt;sub>1&lt;/sub> - r&lt;sub>0&lt;/sub>) + r&lt;sub>0&lt;/sub>&lt;/i>&lt;/blockquote>
    22. 

  22. <span class='line'> 15</span>  *
    23. 

  23. <span class='line'> 16</span>  * For example, a linear scale from the domain [0, 100] to range [0, 640]:
    24. 

  24. <span class='line'> 17</span>  *
    25. 

  25. <span class='line'> 18</span>  * &lt;blockquote>&lt;i>f(x) = (x - 0) / (100 - 0) * (640 - 0) + 0&lt;/i>&lt;br>
    26. 

  26. <span class='line'> 19</span>  * &lt;i>f(x) = x / 100 * 640&lt;/i>&lt;br>
    27. 

  27. <span class='line'> 20</span>  * &lt;i>f(x) = x * 6.4&lt;/i>&lt;br>
    28. 

  28. <span class='line'> 21</span>  * &lt;/blockquote>
    29. 

  29. <span class='line'> 22</span>  *
    30. 

  30. <span class='line'> 23</span>  * Thus, saying
    31. 

  31. <span class='line'> 24</span>  *
    32. 

  32. <span class='line'> 25</span>  * &lt;pre>.height(function(d) d * 6.4)&lt;/pre>
    33. 

  33. <span class='line'> 26</span>  *
    34. 

  34. <span class='line'> 27</span>  * is identical to
    35. 

  35. <span class='line'> 28</span>  *
    36. 

  36. <span class='line'> 29</span>  * &lt;pre>.height(pv.Scale.linear(0, 100).range(0, 640))&lt;/pre>
    37. 

  37. <span class='line'> 30</span>  *
    38. 

  38. <span class='line'> 31</span>  * As you can see, scales do not always make code smaller, but they should make
    39. 

  39. <span class='line'> 32</span>  * code more explicit and easier to maintain. In addition to readability, scales
    40. 

  40. <span class='line'> 33</span>  * offer several useful features:
    41. 

  41. <span class='line'> 34</span>  *
    42. 

  42. <span class='line'> 35</span>  * &lt;p>1. The range can be expressed in colors, rather than pixels. Changing the
    43. 

  43. <span class='line'> 36</span>  * example above to
    44. 

  44. <span class='line'> 37</span>  *
    45. 

  45. <span class='line'> 38</span>  * &lt;pre>.fillStyle(pv.Scale.linear(0, 100).range("red", "green"))&lt;/pre>
    46. 

  46. <span class='line'> 39</span>  *
    47. 

  47. <span class='line'> 40</span>  * will cause it to fill the marks "red" on an input value of 0, "green" on an
    48. 

  48. <span class='line'> 41</span>  * input value of 100, and some color in-between for intermediate values.
    49. 

  49. <span class='line'> 42</span>  *
    50. 

  50. <span class='line'> 43</span>  * &lt;p>2. The domain and range can be subdivided for a "poly-linear"
    51. 

  51. <span class='line'> 44</span>  * transformation. For example, you may want a diverging color scale that is
    52. 

  52. <span class='line'> 45</span>  * increasingly red for negative values, and increasingly green for positive
    53. 

  53. <span class='line'> 46</span>  * values:
    54. 

  54. <span class='line'> 47</span>  *
    55. 

  55. <span class='line'> 48</span>  * &lt;pre>.fillStyle(pv.Scale.linear(-1, 0, 1).range("red", "white", "green"))&lt;/pre>
    56. 

  56. <span class='line'> 49</span>  *
    57. 

  57. <span class='line'> 50</span>  * The domain can be specified as a series of &lt;i>n&lt;/i> monotonically-increasing
    58. 

  58. <span class='line'> 51</span>  * values; the range must also be specified as &lt;i>n&lt;/i> values, resulting in
    59. 

  59. <span class='line'> 52</span>  * &lt;i>n - 1&lt;/i> contiguous linear scales.
    60. 

  60. <span class='line'> 53</span>  *
    61. 

  61. <span class='line'> 54</span>  * &lt;p>3. Linear scales can be inverted for interaction. The {@link #invert}
    62. 

  62. <span class='line'> 55</span>  * method takes a value in the output range, and returns the corresponding value
    63. 

  63. <span class='line'> 56</span>  * in the input domain. This is frequently used to convert the mouse location
    64. 

  64. <span class='line'> 57</span>  * (see {@link pv.Mark#mouse}) to a value in the input domain. Note that
    65. 

  65. <span class='line'> 58</span>  * inversion is only supported for numeric ranges, and not colors.
    66. 

  66. <span class='line'> 59</span>  *
    67. 

  67. <span class='line'> 60</span>  * &lt;p>4. A scale can be queried for reasonable "tick" values. The {@link #ticks}
    68. 

  68. <span class='line'> 61</span>  * method provides a convenient way to get a series of evenly-spaced rounded
    69. 

  69. <span class='line'> 62</span>  * values in the input domain. Frequently these are used in conjunction with
    70. 

  70. <span class='line'> 63</span>  * {@link pv.Rule} to display tick marks or grid lines.
    71. 

  71. <span class='line'> 64</span>  *
    72. 

  72. <span class='line'> 65</span>  * &lt;p>5. A scale can be "niced" to extend the domain to suitable rounded
    73. 

  73. <span class='line'> 66</span>  * numbers. If the minimum and maximum of the domain are messy because they are
    74. 

  74. <span class='line'> 67</span>  * derived from data, you can use {@link #nice} to round these values down and
    75. 

  75. <span class='line'> 68</span>  * up to even numbers.
    76. 

  76. <span class='line'> 69</span>  *
    77. 

  77. <span class='line'> 70</span>  * @param {number...} domain... domain values.
    78. 

  78. <span class='line'> 71</span>  * @returns {pv.Scale.linear} a linear scale.
    79. 

  79. <span class='line'> 72</span>  */</span><span class="WHIT">
    80. 

  80. <span class='line'> 73</span> </span><span class="NAME">pv.Scale.linear</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    81. 

  81. <span class='line'> 74</span> </span><span class="WHIT">  </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">d</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="NUMB">0</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">r</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="NUMB">0</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">i</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="NAME">pv.identity</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">precision</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NUMB">0</span><span class="PUNC">;</span><span class="WHIT">
    82. 

  82. <span class='line'> 75</span> 
    83. 

  83. <span class='line'> 76</span> </span><span class="WHIT">  </span><span class="COMM">/** @private */</span><span class="WHIT">
    84. 

  84. <span class='line'> 77</span> </span><span class="WHIT">  </span><span class="KEYW">function</span><span class="WHIT"> </span><span class="NAME">scale</span><span class="PUNC">(</span><span class="NAME">x</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    85. 

  85. <span class='line'> 78</span> </span><span class="WHIT">    </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">pv.search</span><span class="PUNC">(</span><span class="NAME">d</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">x</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    86. 

  86. <span class='line'> 79</span> </span><span class="WHIT">    </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">0</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">2</span><span class="PUNC">;</span><span class="WHIT">
    87. 

  87. <span class='line'> 80</span> </span><span class="WHIT">    </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.max</span><span class="PUNC">(</span><span class="NUMB">0</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">Math.min</span><span class="PUNC">(</span><span class="NAME">i.length</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">j</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    88. 

  88. <span class='line'> 81</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">i</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">(</span><span class="PUNC">(</span><span class="NAME">x</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    89. 

  89. <span class='line'> 82</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="WHIT">
    90. 

  90. <span class='line'> 83</span> 
    91. 

  91. <span class='line'> 84</span> </span><span class="WHIT">  </span><span class="COMM">/**
    92. 

  92. <span class='line'> 85</span>    * Sets or gets the input domain. This method can be invoked several ways:
    93. 

  93. <span class='line'> 86</span>    *
    94. 

  94. <span class='line'> 87</span>    * &lt;p>1. &lt;tt>domain(min, ..., max)&lt;/tt>
    95. 

  95. <span class='line'> 88</span>    *
    96. 

  96. <span class='line'> 89</span>    * &lt;p>Specifying the domain as a series of numbers is the most explicit and
    97. 

  97. <span class='line'> 90</span>    * recommended approach. Most commonly, two numbers are specified: the minimum
    98. 

  98. <span class='line'> 91</span>    * and maximum value. However, for a diverging scale, or other subdivided
    99. 

  99. <span class='line'> 92</span>    * poly-linear scales, multiple values can be specified. Values can be derived
    100. 

  100. <span class='line'> 93</span>    * from data using {@link pv.min} and {@link pv.max}. For example:
    101. 

  101. <span class='line'> 94</span>    *
    102. 

  102. <span class='line'> 95</span>    * &lt;pre>.domain(0, pv.max(array))&lt;/pre>
    103. 

  103. <span class='line'> 96</span>    *
    104. 

  104. <span class='line'> 97</span>    * An alternative method for deriving minimum and maximum values from data
    105. 

  105. <span class='line'> 98</span>    * follows.
    106. 

  106. <span class='line'> 99</span>    *
    107. 

  107. <span class='line'>100</span>    * &lt;p>2. &lt;tt>domain(array, minf, maxf)&lt;/tt>
    108. 

  108. <span class='line'>101</span>    *
    109. 

  109. <span class='line'>102</span>    * &lt;p>When both the minimum and maximum value are derived from data, the
    110. 

  110. <span class='line'>103</span>    * arguments to the &lt;tt>domain&lt;/tt> method can be specified as the array of
    111. 

  111. <span class='line'>104</span>    * data, followed by zero, one or two accessor functions. For example, if the
    112. 

  112. <span class='line'>105</span>    * array of data is just an array of numbers:
    113. 

  113. <span class='line'>106</span>    *
    114. 

  114. <span class='line'>107</span>    * &lt;pre>.domain(array)&lt;/pre>
    115. 

  115. <span class='line'>108</span>    *
    116. 

  116. <span class='line'>109</span>    * On the other hand, if the array elements are objects representing stock
    117. 

  117. <span class='line'>110</span>    * values per day, and the domain should consider the stock's daily low and
    118. 

  118. <span class='line'>111</span>    * daily high:
    119. 

  119. <span class='line'>112</span>    *
    120. 

  120. <span class='line'>113</span>    * &lt;pre>.domain(array, function(d) d.low, function(d) d.high)&lt;/pre>
    121. 

  121. <span class='line'>114</span>    *
    122. 

  122. <span class='line'>115</span>    * The first method of setting the domain is preferred because it is more
    123. 

  123. <span class='line'>116</span>    * explicit; setting the domain using this second method should be used only
    124. 

  124. <span class='line'>117</span>    * if brevity is required.
    125. 

  125. <span class='line'>118</span>    *
    126. 

  126. <span class='line'>119</span>    * &lt;p>3. &lt;tt>domain()&lt;/tt>
    127. 

  127. <span class='line'>120</span>    *
    128. 

  128. <span class='line'>121</span>    * &lt;p>Invoking the &lt;tt>domain&lt;/tt> method with no arguments returns the
    129. 

  129. <span class='line'>122</span>    * current domain as an array of numbers.
    130. 

  130. <span class='line'>123</span>    *
    131. 

  131. <span class='line'>124</span>    * @function
    132. 

  132. <span class='line'>125</span>    * @name pv.Scale.linear.prototype.domain
    133. 

  133. <span class='line'>126</span>    * @param {number...} domain... domain values.
    134. 

  134. <span class='line'>127</span>    * @returns {pv.Scale.linear} &lt;tt>this&lt;/tt>, or the current domain.
    135. 

  135. <span class='line'>128</span>    */</span><span class="WHIT">
    136. 

  136. <span class='line'>129</span> </span><span class="WHIT">  </span><span class="NAME">scale.domain</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="NAME">array</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">min</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">max</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    137. 

  137. <span class='line'>130</span> </span><span class="WHIT">    </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">arguments.length</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    138. 

  138. <span class='line'>131</span> </span><span class="WHIT">      </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">array</span><span class="WHIT"> </span><span class="KEYW">instanceof</span><span class="WHIT"> </span><span class="NAME">Array</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    139. 

  139. <span class='line'>132</span> </span><span class="WHIT">        </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">arguments.length</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">2</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">min</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">pv.identity</span><span class="PUNC">;</span><span class="WHIT">
    140. 

  140. <span class='line'>133</span> </span><span class="WHIT">        </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">arguments.length</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">3</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">min</span><span class="PUNC">;</span><span class="WHIT">
    141. 

  141. <span class='line'>134</span> </span><span class="WHIT">        </span><span class="NAME">d</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="NAME">pv.min</span><span class="PUNC">(</span><span class="NAME">array</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">min</span><span class="PUNC">)</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">pv.max</span><span class="PUNC">(</span><span class="NAME">array</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">max</span><span class="PUNC">)</span><span class="PUNC">]</span><span class="PUNC">;</span><span class="WHIT">
    142. 

  142. <span class='line'>135</span> </span><span class="WHIT">      </span><span class="PUNC">}</span><span class="WHIT"> </span><span class="KEYW">else</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    143. 

  143. <span class='line'>136</span> </span><span class="WHIT">        </span><span class="NAME">d</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Array.prototype.slice.call</span><span class="PUNC">(</span><span class="NAME">arguments</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    144. 

  144. <span class='line'>137</span> </span><span class="WHIT">      </span><span class="PUNC">}</span><span class="WHIT">
    145. 

  145. <span class='line'>138</span> </span><span class="WHIT">      </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="KEYW">this</span><span class="PUNC">;</span><span class="WHIT">
    146. 

  146. <span class='line'>139</span> </span><span class="WHIT">    </span><span class="PUNC">}</span><span class="WHIT">
    147. 

  147. <span class='line'>140</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">;</span><span class="WHIT">
    148. 

  148. <span class='line'>141</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    149. 

  149. <span class='line'>142</span> 
    150. 

  150. <span class='line'>143</span> </span><span class="WHIT">  </span><span class="COMM">/**
    151. 

  151. <span class='line'>144</span>    * Sets or gets the output range. This method can be invoked several ways:
    152. 

  152. <span class='line'>145</span>    *
    153. 

  153. <span class='line'>146</span>    * &lt;p>1. &lt;tt>range(min, ..., max)&lt;/tt>
    154. 

  154. <span class='line'>147</span>    *
    155. 

  155. <span class='line'>148</span>    * &lt;p>The range may be specified as a series of numbers or colors. Most
    156. 

  156. <span class='line'>149</span>    * commonly, two numbers are specified: the minimum and maximum pixel values.
    157. 

  157. <span class='line'>150</span>    * For a color scale, values may be specified as {@link pv.Color}s or
    158. 

  158. <span class='line'>151</span>    * equivalent strings. For a diverging scale, or other subdivided poly-linear
    159. 

  159. <span class='line'>152</span>    * scales, multiple values can be specified. For example:
    160. 

  160. <span class='line'>153</span>    *
    161. 

  161. <span class='line'>154</span>    * &lt;pre>.range("red", "white", "green")&lt;/pre>
    162. 

  162. <span class='line'>155</span>    *
    163. 

  163. <span class='line'>156</span>    * &lt;p>Currently, only numbers and colors are supported as range values. The
    164. 

  164. <span class='line'>157</span>    * number of range values must exactly match the number of domain values, or
    165. 

  165. <span class='line'>158</span>    * the behavior of the scale is undefined.
    166. 

  166. <span class='line'>159</span>    *
    167. 

  167. <span class='line'>160</span>    * &lt;p>2. &lt;tt>range()&lt;/tt>
    168. 

  168. <span class='line'>161</span>    *
    169. 

  169. <span class='line'>162</span>    * &lt;p>Invoking the &lt;tt>range&lt;/tt> method with no arguments returns the current
    170. 

  170. <span class='line'>163</span>    * range as an array of numbers or colors.
    171. 

  171. <span class='line'>164</span>    *
    172. 

  172. <span class='line'>165</span>    * @function
    173. 

  173. <span class='line'>166</span>    * @name pv.Scale.linear.prototype.range
    174. 

  174. <span class='line'>167</span>    * @param {...} range... range values.
    175. 

  175. <span class='line'>168</span>    * @returns {pv.Scale.linear} &lt;tt>this&lt;/tt>, or the current range.
    176. 

  176. <span class='line'>169</span>    */</span><span class="WHIT">
    177. 

  177. <span class='line'>170</span> </span><span class="WHIT">  </span><span class="NAME">scale.range</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    178. 

  178. <span class='line'>171</span> </span><span class="WHIT">    </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">arguments.length</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    179. 

  179. <span class='line'>172</span> </span><span class="WHIT">      </span><span class="NAME">r</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Array.prototype.slice.call</span><span class="PUNC">(</span><span class="NAME">arguments</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    180. 

  180. <span class='line'>173</span> </span><span class="WHIT">      </span><span class="NAME">i</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="PUNC">]</span><span class="PUNC">;</span><span class="WHIT">
    181. 

  181. <span class='line'>174</span> </span><span class="WHIT">      </span><span class="KEYW">for</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NUMB">0</span><span class="PUNC">;</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NAME">r.length</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">;</span><span class="WHIT"> </span><span class="NAME">j</span><span class="PUNC">++</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    182. 

  182. <span class='line'>175</span> </span><span class="WHIT">        </span><span class="NAME">i.push</span><span class="PUNC">(</span><span class="NAME">pv.Scale.interpolator</span><span class="PUNC">(</span><span class="NAME">r</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">r</span><span class="PUNC">[</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    183. 

  183. <span class='line'>176</span> </span><span class="WHIT">      </span><span class="PUNC">}</span><span class="WHIT">
    184. 

  184. <span class='line'>177</span> </span><span class="WHIT">      </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="KEYW">this</span><span class="PUNC">;</span><span class="WHIT">
    185. 

  185. <span class='line'>178</span> </span><span class="WHIT">    </span><span class="PUNC">}</span><span class="WHIT">
    186. 

  186. <span class='line'>179</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">r</span><span class="PUNC">;</span><span class="WHIT">
    187. 

  187. <span class='line'>180</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    188. 

  188. <span class='line'>181</span> 
    189. 

  189. <span class='line'>182</span> </span><span class="WHIT">  </span><span class="COMM">/**
    190. 

  190. <span class='line'>183</span>    * Inverts the specified value in the output range, returning the
    191. 

  191. <span class='line'>184</span>    * corresponding value in the input domain. This is frequently used to convert
    192. 

  192. <span class='line'>185</span>    * the mouse location (see {@link pv.Mark#mouse}) to a value in the input
    193. 

  193. <span class='line'>186</span>    * domain. Inversion is only supported for numeric ranges, and not colors.
    194. 

  194. <span class='line'>187</span>    *
    195. 

  195. <span class='line'>188</span>    * &lt;p>Note that this method does not do any rounding or bounds checking. If
    196. 

  196. <span class='line'>189</span>    * the input domain is discrete (e.g., an array index), the returned value
    197. 

  197. <span class='line'>190</span>    * should be rounded. If the specified &lt;tt>y&lt;/tt> value is outside the range,
    198. 

  198. <span class='line'>191</span>    * the returned value may be equivalently outside the input domain.
    199. 

  199. <span class='line'>192</span>    *
    200. 

  200. <span class='line'>193</span>    * @function
    201. 

  201. <span class='line'>194</span>    * @name pv.Scale.linear.prototype.invert
    202. 

  202. <span class='line'>195</span>    * @param {number} y a value in the output range (a pixel location).
    203. 

  203. <span class='line'>196</span>    * @returns {number} a value in the input domain.
    204. 

  204. <span class='line'>197</span>    */</span><span class="WHIT">
    205. 

  205. <span class='line'>198</span> </span><span class="WHIT">  </span><span class="NAME">scale.invert</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="NAME">y</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    206. 

  206. <span class='line'>199</span> </span><span class="WHIT">    </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">pv.search</span><span class="PUNC">(</span><span class="NAME">r</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">y</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    207. 

  207. <span class='line'>200</span> </span><span class="WHIT">    </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">0</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">2</span><span class="PUNC">;</span><span class="WHIT">
    208. 

  208. <span class='line'>201</span> </span><span class="WHIT">    </span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.max</span><span class="PUNC">(</span><span class="NUMB">0</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">Math.min</span><span class="PUNC">(</span><span class="NAME">i.length</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">j</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    209. 

  209. <span class='line'>202</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">y</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">r</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">r</span><span class="PUNC">[</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">r</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">*</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">j</span><span class="PUNC">]</span><span class="PUNC">;</span><span class="WHIT">
    210. 

  210. <span class='line'>203</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    211. 

  211. <span class='line'>204</span> 
    212. 

  212. <span class='line'>205</span> </span><span class="WHIT">  </span><span class="COMM">/**
    213. 

  213. <span class='line'>206</span>    * Returns an array of evenly-spaced, suitably-rounded values in the input
    214. 

  214. <span class='line'>207</span>    * domain. This method attempts to return between 5 and 10 tick values. These
    215. 

  215. <span class='line'>208</span>    * values are frequently used in conjunction with {@link pv.Rule} to display
    216. 

  216. <span class='line'>209</span>    * tick marks or grid lines.
    217. 

  217. <span class='line'>210</span>    *
    218. 

  218. <span class='line'>211</span>    * @function
    219. 

  219. <span class='line'>212</span>    * @name pv.Scale.linear.prototype.ticks
    220. 

  220. <span class='line'>213</span>    * @returns {number[]} an array input domain values to use as ticks.
    221. 

  221. <span class='line'>214</span>    */</span><span class="WHIT">
    222. 

  222. <span class='line'>215</span> </span><span class="WHIT">  </span><span class="NAME">scale.ticks</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    223. 

  223. <span class='line'>216</span> </span><span class="WHIT">    </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">min</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NUMB">0</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT">
    224. 

  224. <span class='line'>217</span> </span><span class="WHIT">        </span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">d.length</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT">
    225. 

  225. <span class='line'>218</span> </span><span class="WHIT">        </span><span class="NAME">span</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">min</span><span class="PUNC">,</span><span class="WHIT">
    226. 

  226. <span class='line'>219</span> </span><span class="WHIT">        </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">pv.logCeil</span><span class="PUNC">(</span><span class="NAME">span</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NUMB">10</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NUMB">10</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    227. 

  227. <span class='line'>220</span> </span><span class="WHIT">    </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">span</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">2</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NUMB">5</span><span class="PUNC">;</span><span class="WHIT">
    228. 

  228. <span class='line'>221</span> </span><span class="WHIT">    </span><span class="KEYW">else</span><span class="WHIT"> </span><span class="KEYW">if</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="NAME">span</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">&lt;</span><span class="WHIT"> </span><span class="NUMB">5</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NUMB">2</span><span class="PUNC">;</span><span class="WHIT">
    229. 

  229. <span class='line'>222</span> </span><span class="WHIT">    </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">start</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.ceil</span><span class="PUNC">(</span><span class="NAME">min</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">*</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">,</span><span class="WHIT">
    230. 

  230. <span class='line'>223</span> </span><span class="WHIT">        </span><span class="NAME">end</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.floor</span><span class="PUNC">(</span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">*</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">;</span><span class="WHIT">
    231. 

  231. <span class='line'>224</span> </span><span class="WHIT">    </span><span class="NAME">precision</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.max</span><span class="PUNC">(</span><span class="NUMB">0</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="NAME">Math.floor</span><span class="PUNC">(</span><span class="NAME">pv.log</span><span class="PUNC">(</span><span class="NAME">step</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NUMB">10</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="PUNC">.</span><span class="NUMB">01</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    232. 

  232. <span class='line'>225</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">pv.range</span><span class="PUNC">(</span><span class="NAME">start</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">end</span><span class="WHIT"> </span><span class="PUNC">+</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    233. 

  233. <span class='line'>226</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    234. 

  234. <span class='line'>227</span> 
    235. 

  235. <span class='line'>228</span> </span><span class="WHIT">  </span><span class="COMM">/**
    236. 

  236. <span class='line'>229</span>    * Formats the specified tick value using the appropriate precision, based on
    237. 

  237. <span class='line'>230</span>    * the step interval between tick marks.
    238. 

  238. <span class='line'>231</span>    *
    239. 

  239. <span class='line'>232</span>    * @function
    240. 

  240. <span class='line'>233</span>    * @name pv.Scale.linear.prototype.tickFormat
    241. 

  241. <span class='line'>234</span>    * @param {number} t a tick value.
    242. 

  242. <span class='line'>235</span>    * @return {string} a formatted tick value.
    243. 

  243. <span class='line'>236</span>    */</span><span class="WHIT">
    244. 

  244. <span class='line'>237</span> </span><span class="WHIT">  </span><span class="NAME">scale.tickFormat</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="NAME">t</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    245. 

  245. <span class='line'>238</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">t.toFixed</span><span class="PUNC">(</span><span class="NAME">precision</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    246. 

  246. <span class='line'>239</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    247. 

  247. <span class='line'>240</span> 
    248. 

  248. <span class='line'>241</span> </span><span class="WHIT">  </span><span class="COMM">/**
    249. 

  249. <span class='line'>242</span>    * "Nices" this scale, extending the bounds of the input domain to
    250. 

  250. <span class='line'>243</span>    * evenly-rounded values. Nicing is useful if the domain is computed
    251. 

  251. <span class='line'>244</span>    * dynamically from data, and may be irregular. For example, given a domain of
    252. 

  252. <span class='line'>245</span>    * [0.20147987687960267, 0.996679553296417], a call to &lt;tt>nice()&lt;/tt> might
    253. 

  253. <span class='line'>246</span>    * extend the domain to [0.2, 1].
    254. 

  254. <span class='line'>247</span>    *
    255. 

  255. <span class='line'>248</span>    * &lt;p>This method must be invoked each time after setting the domain.
    256. 

  256. <span class='line'>249</span>    *
    257. 

  257. <span class='line'>250</span>    * @function
    258. 

  258. <span class='line'>251</span>    * @name pv.Scale.linear.prototype.nice
    259. 

  259. <span class='line'>252</span>    * @returns {pv.Scale.linear} &lt;tt>this&lt;/tt>.
    260. 

  260. <span class='line'>253</span>    */</span><span class="WHIT">
    261. 

  261. <span class='line'>254</span> </span><span class="WHIT">  </span><span class="NAME">scale.nice</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    262. 

  262. <span class='line'>255</span> </span><span class="WHIT">    </span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">min</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NUMB">0</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT">
    263. 

  263. <span class='line'>256</span> </span><span class="WHIT">        </span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">d</span><span class="PUNC">[</span><span class="NAME">d.length</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">]</span><span class="PUNC">,</span><span class="WHIT">
    264. 

  264. <span class='line'>257</span> </span><span class="WHIT">        </span><span class="NAME">step</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">Math.pow</span><span class="PUNC">(</span><span class="NUMB">10</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">Math.round</span><span class="PUNC">(</span><span class="NAME">Math.log</span><span class="PUNC">(</span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NAME">min</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">Math.log</span><span class="PUNC">(</span><span class="NUMB">10</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">-</span><span class="WHIT"> </span><span class="NUMB">1</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    265. 

  265. <span class='line'>258</span> </span><span class="WHIT">    </span><span class="NAME">d</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="PUNC">[</span><span class="NAME">Math.floor</span><span class="PUNC">(</span><span class="NAME">min</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">*</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">Math.ceil</span><span class="PUNC">(</span><span class="NAME">max</span><span class="WHIT"> </span><span class="PUNC">/</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">*</span><span class="WHIT"> </span><span class="NAME">step</span><span class="PUNC">]</span><span class="PUNC">;</span><span class="WHIT">
    266. 

  266. <span class='line'>259</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="KEYW">this</span><span class="PUNC">;</span><span class="WHIT">
    267. 

  267. <span class='line'>260</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    268. 

  268. <span class='line'>261</span> 
    269. 

  269. <span class='line'>262</span> </span><span class="WHIT">  </span><span class="COMM">/**
    270. 

  270. <span class='line'>263</span>    * Returns a view of this scale by the specified accessor function &lt;tt>f&lt;/tt>.
    271. 

  271. <span class='line'>264</span>    * Given a scale &lt;tt>y&lt;/tt>, &lt;tt>y.by(function(d) d.foo)&lt;/tt> is equivalent to
    272. 

  272. <span class='line'>265</span>    * &lt;tt>function(d) y(d.foo)&lt;/tt>.
    273. 

  273. <span class='line'>266</span>    *
    274. 

  274. <span class='line'>267</span>    * &lt;p>This method is provided for convenience, such that scales can be
    275. 

  275. <span class='line'>268</span>    * succinctly defined inline. For example, given an array of data elements
    276. 

  276. <span class='line'>269</span>    * that have a &lt;tt>score&lt;/tt> attribute with the domain [0, 1], the height
    277. 

  277. <span class='line'>270</span>    * property could be specified as:
    278. 

  278. <span class='line'>271</span>    *
    279. 

  279. <span class='line'>272</span>    * &lt;pre>.height(pv.Scale.linear().range(0, 480).by(function(d) d.score))&lt;/pre>
    280. 

  280. <span class='line'>273</span>    *
    281. 

  281. <span class='line'>274</span>    * This is equivalent to:
    282. 

  282. <span class='line'>275</span>    *
    283. 

  283. <span class='line'>276</span>    * &lt;pre>.height(function(d) d.score * 480)&lt;/pre>
    284. 

  284. <span class='line'>277</span>    *
    285. 

  285. <span class='line'>278</span>    * This method should be used judiciously; it is typically more clear to
    286. 

  286. <span class='line'>279</span>    * invoke the scale directly, passing in the value to be scaled.
    287. 

  287. <span class='line'>280</span>    *
    288. 

  288. <span class='line'>281</span>    * @function
    289. 

  289. <span class='line'>282</span>    * @name pv.Scale.linear.prototype.by
    290. 

  290. <span class='line'>283</span>    * @param {function} f an accessor function.
    291. 

  291. <span class='line'>284</span>    * @returns {pv.Scale.linear} a view of this scale by the specified accessor
    292. 

  292. <span class='line'>285</span>    * function.
    293. 

  293. <span class='line'>286</span>    */</span><span class="WHIT">
    294. 

  294. <span class='line'>287</span> </span><span class="WHIT">  </span><span class="NAME">scale.by</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="KEYW">function</span><span class="PUNC">(</span><span class="NAME">f</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT">
    295. 

  295. <span class='line'>288</span> </span><span class="WHIT">    </span><span class="KEYW">function</span><span class="WHIT"> </span><span class="NAME">by</span><span class="PUNC">(</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="PUNC">{</span><span class="WHIT"> </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">scale</span><span class="PUNC">(</span><span class="NAME">f.apply</span><span class="PUNC">(</span><span class="KEYW">this</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">arguments</span><span class="PUNC">)</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT"> </span><span class="PUNC">}</span><span class="WHIT">
    296. 

  296. <span class='line'>289</span> </span><span class="WHIT">    </span><span class="KEYW">for</span><span class="WHIT"> </span><span class="PUNC">(</span><span class="KEYW">var</span><span class="WHIT"> </span><span class="NAME">method</span><span class="WHIT"> </span><span class="KEYW">in</span><span class="WHIT"> </span><span class="NAME">scale</span><span class="PUNC">)</span><span class="WHIT"> </span><span class="NAME">by</span><span class="PUNC">[</span><span class="NAME">method</span><span class="PUNC">]</span><span class="WHIT"> </span><span class="PUNC">=</span><span class="WHIT"> </span><span class="NAME">scale</span><span class="PUNC">[</span><span class="NAME">method</span><span class="PUNC">]</span><span class="PUNC">;</span><span class="WHIT">
    297. 

  297. <span class='line'>290</span> </span><span class="WHIT">    </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">by</span><span class="PUNC">;</span><span class="WHIT">
    298. 

  298. <span class='line'>291</span> </span><span class="WHIT">  </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    299. 

  299. <span class='line'>292</span> 
    300. 

  300. <span class='line'>293</span> </span><span class="WHIT">  </span><span class="NAME">scale.domain.apply</span><span class="PUNC">(</span><span class="NAME">scale</span><span class="PUNC">,</span><span class="WHIT"> </span><span class="NAME">arguments</span><span class="PUNC">)</span><span class="PUNC">;</span><span class="WHIT">
    301. 

  301. <span class='line'>294</span> </span><span class="WHIT">  </span><span class="KEYW">return</span><span class="WHIT"> </span><span class="NAME">scale</span><span class="PUNC">;</span><span class="WHIT">
    302. 

  302. <span class='line'>295</span> </span><span class="PUNC">}</span><span class="PUNC">;</span><span class="WHIT">
    303. 

  303. <span class='line'>296</span> </span></pre></body></html>
    304.