pixel-editor/js/_changeZoom.js
2021-10-27 10:02:21 +02:00

76 lines
2.1 KiB
JavaScript

/** Changes the zoom level of the canvas
* @param {*} direction 'in' or 'out'
* @param {*} cursorLocation The position of the cursor when the user zoomed
*/
function changeZoom (direction, cursorLocation) {
// Computing current width and height
let oldWidth = canvasSize[0] * zoom;
let oldHeight = canvasSize[1] * zoom;
let newWidth, newHeight;
let prevZoom = zoom;
let zoomed = false;
//change zoom level
//if you want to zoom out, and the zoom isnt already at the smallest level
if (direction == 'out' && zoom > MIN_ZOOM_LEVEL) {
zoomed = true;
if (zoom > 2)
zoom -= Math.ceil(zoom / 10);
else
zoom -= Math.ceil(zoom * 2 / 10) / 2;
newWidth = canvasSize[0] * zoom;
newHeight = canvasSize[1] * zoom;
//adjust canvas position
layers[0].setCanvasOffset(
layers[0].canvas.offsetLeft + (oldWidth - newWidth) * cursorLocation[0]/oldWidth,
layers[0].canvas.offsetTop + (oldHeight - newHeight) * cursorLocation[1]/oldHeight);
}
//if you want to zoom in
else if (direction == 'in' && zoom + Math.ceil(zoom/10) < window.innerHeight/4) {
zoomed = true;
if (zoom > 2)
zoom += Math.ceil(zoom/10);
else {
if (zoom + zoom/10 > 2) {
zoom += Math.ceil(zoom/10);
zoom = Math.ceil(zoom);
}
else {
zoom += Math.ceil(zoom * 2 / 10) / 2;
}
}
newWidth = canvasSize[0] * zoom;
newHeight = canvasSize[1] * zoom;
//adjust canvas position
layers[0].setCanvasOffset(
layers[0].canvas.offsetLeft - Math.round((newWidth - oldWidth)*cursorLocation[0]/oldWidth),
layers[0].canvas.offsetTop - Math.round((newHeight - oldHeight)*cursorLocation[1]/oldHeight));
}
//resize canvas
layers[0].resize();
// adjust brush size
ToolManager.currentTool().updateCursor();
// Adjust pixel grid thickness
if (zoomed) {
if (zoom <= 7)
disablePixelGrid();
else if (zoom >= 20 && direction == 'in') {
enablePixelGrid();
repaintPixelGrid((zoom - prevZoom) * 0.6);
}
else if (prevZoom >= 20 && direction == 'out') {
enablePixelGrid();
repaintPixelGrid((zoom - prevZoom) * 0.6);
}
else {
enablePixelGrid();
}
}
}