pixel-editor/js/_drawLine.js
npalomba ab070db6a3 Fixed bug that caused the eraser preview to be shifted from the actual mouse position.
Signed-off-by: npalomba <nicola.palomba@studenti.galileilivorno.gov.it>
2019-04-01 22:16:07 +02:00

27 lines
851 B
JavaScript

//draw a line between two points on canvas
function line(x0,y0,x1,y1) {
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') {
// 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;}
}
}