基於HTML5 Canvas和jQuery的畫圖工具的實現
阿新 • • 發佈：2019-01-07
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//undo redo
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var history =new Array();
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var cStep = -1;
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/**
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* put current canvas to cache
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*/
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function historyPush()
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{
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cStep++;
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if (cStep < history.length)
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{
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history.length = cStep;
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}
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history.push($("#myCanvas").get(0).toDataURL());
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}
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/**
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* function: undo
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*/
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function undo()
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{
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if (cStep >= 0)
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{
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cStep--;
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var tempImage = new Image();
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tempImage.src = history[cStep];
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tempImage.onload = function () { ctx.drawImage(tempImage, 0, 0);};
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}
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}
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/**
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* function: redo
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*/
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function redo()
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{
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if (cStep <history.length-1)
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{
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clearCanvas();
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cStep++;
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var tempImage = new Image();
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tempImage.src = history[cStep];
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tempImage.onload = function () { ctx.drawImage(tempImage, 0, 0); };
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}
- }