56 lines
1.9 KiB
JavaScript
56 lines
1.9 KiB
JavaScript
//draw a line between two points on canvas
|
|
function line(x0, y0, x1, y1, brushSize) {
|
|
|
|
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 == 'pencil' || currentTool == 'rectangle') {
|
|
// I fill the rect
|
|
currentLayer.context.fillRect(x0-Math.floor(brushSize/2), y0-Math.floor(brushSize/2), brushSize, brushSize);
|
|
} else if (currentTool == 'eraser') {
|
|
// In case I'm using the eraser I must clear the rect
|
|
currentLayer.context.clearRect(x0-Math.floor(eraserSize/2), y0-Math.floor(eraserSize/2), eraserSize, eraserSize);
|
|
}
|
|
|
|
//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;}
|
|
if (e2 < dx) {err +=dx; y0+=sy;}
|
|
}
|
|
}
|
|
|
|
// draw a line between two points on canvas
|
|
function lineOnLayer(x0, y0, x1, y1, brushSize, context) {
|
|
|
|
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 == 'pencil' || currentTool == 'rectangle') {
|
|
// I fill the rect
|
|
context.fillRect(x0-Math.floor(brushSize/2), y0-Math.floor(brushSize/2), brushSize, brushSize);
|
|
} else if (currentTool == 'eraser') {
|
|
// In case I'm using the eraser I must clear the rect
|
|
context.clearRect(x0-Math.floor(eraserSize/2), y0-Math.floor(eraserSize/2), eraserSize, eraserSize);
|
|
}
|
|
|
|
// 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;}
|
|
if (e2 < dx) {err +=dx; y0+=sy;}
|
|
}
|
|
}
|