pixel-editor/js/_drawLine.js

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//draw a line between two points on canvas
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function line(x0,y0,x1,y1, brushSize) {
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var dx = Math.abs(x1-x0);
var dy = Math.abs(y1-y0);
var sx = (x0 < x1 ? 1 : -1);
var sy = (y0 < y1 ? 1 : -1);
var err = dx-dy;
while (true) {
//set pixel
// If the current tool is the brush
if (currentTool.name == 'pencil' || currentTool.name == 'rectangle') {
// I fill the rect
currentLayer.context.fillRect(x0-Math.floor(brushSize/2), y0-Math.floor(brushSize/2), brushSize, brushSize);
} else if (currentTool.name == 'eraser') {
// In case I'm using the eraser I must clear the rect
currentLayer.context.clearRect(x0-Math.floor(tool.eraser.brushSize/2), y0-Math.floor(tool.eraser.brushSize/2), tool.eraser.brushSize, tool.eraser.brushSize);
}
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//if we've reached the end goal, exit the loop
if ((x0==x1) && (y0==y1)) break;
var e2 = 2*err;
if (e2 >-dy) {
err -=dy;
x0+=sx;
}
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if (e2 < dx) {
err +=dx;
y0+=sy;
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}
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}
}