95 lines
2.4 KiB
JavaScript
95 lines
2.4 KiB
JavaScript
//>>built
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// Various generic utilities to deal with a linear gradient
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define("dojox/gfx/gradutils", ["./_base", "dojo/_base/lang", "./matrix", "dojo/_base/Color"],
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function(g, lang, m, Color){
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/*===== g= dojox.gfx =====*/
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var gradutils = g.gradutils = {};
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/*===== g= dojox.gfx; gradutils = dojox.gfx.gradutils; =====*/
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function findColor(o, c){
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if(o <= 0){
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return c[0].color;
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}
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var len = c.length;
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if(o >= 1){
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return c[len - 1].color;
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}
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//TODO: use binary search
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for(var i = 0; i < len; ++i){
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var stop = c[i];
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if(stop.offset >= o){
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if(i){
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var prev = c[i - 1];
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return Color.blendColors(new Color(prev.color), new Color(stop.color),
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(o - prev.offset) / (stop.offset - prev.offset));
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}
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return stop.color;
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}
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}
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return c[len - 1].color;
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}
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gradutils.getColor = function(fill, pt){
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// summary:
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// sample a color from a gradient using a point
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// fill: Object:
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// fill object
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// pt: dojox.gfx.Point:
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// point where to sample a color
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var o;
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if(fill){
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switch(fill.type){
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case "linear":
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var angle = Math.atan2(fill.y2 - fill.y1, fill.x2 - fill.x1),
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rotation = m.rotate(-angle),
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projection = m.project(fill.x2 - fill.x1, fill.y2 - fill.y1),
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p = m.multiplyPoint(projection, pt),
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pf1 = m.multiplyPoint(projection, fill.x1, fill.y1),
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pf2 = m.multiplyPoint(projection, fill.x2, fill.y2),
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scale = m.multiplyPoint(rotation, pf2.x - pf1.x, pf2.y - pf1.y).x;
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o = m.multiplyPoint(rotation, p.x - pf1.x, p.y - pf1.y).x / scale;
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break;
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case "radial":
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var dx = pt.x - fill.cx, dy = pt.y - fill.cy;
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o = Math.sqrt(dx * dx + dy * dy) / fill.r;
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break;
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}
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return findColor(o, fill.colors); // dojo.Color
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}
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// simple color
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return new Color(fill || [0, 0, 0, 0]); // dojo.Color
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};
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gradutils.reverse = function(fill){
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// summary:
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// reverses a gradient
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// fill: Object:
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// fill object
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if(fill){
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switch(fill.type){
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case "linear":
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case "radial":
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fill = lang.delegate(fill);
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if(fill.colors){
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var c = fill.colors, l = c.length, i = 0, stop,
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n = fill.colors = new Array(c.length);
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for(; i < l; ++i){
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stop = c[i];
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n[i] = {
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offset: 1 - stop.offset,
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color: stop.color
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};
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}
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n.sort(function(a, b){ return a.offset - b.offset; });
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}
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break;
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}
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}
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return fill; // Object
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};
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return gradutils;
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});
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