thumbpreview.onclick = null; // setup once
const cropinput = document.getElementById('crop32');
const imgselect = thumbpreview.children[0];
- const border = [300,200];
- let crop = cropinput.value.split(/[^0-9]/).map(pos => pos / 1000);
- let scale = 1 / (crop[2] - crop[0]) || 1;
+ const canvas = [thumbpreview.clientWidth, thumbpreview.clientHeight];
+ const border = [canvas[0], canvas[0] * imgpreview.height / imgpreview.width];
+ const minscale = Math.max(1, canvas[1] / border[1]); // 100% or fit width
+ let crop = cropinput.value.split(/[^0-9.]/).map(pos => pos / 1000);
+ let scale = 1 / (crop[2] - crop[0]) || minscale;
crop.push(0); // defined y dimension
crop.splice(2); // end coordinates applied to zoom
crop = crop.map((rel, axis) => rel * border[axis % 2] * scale);
function recrop() {
[0, 1].forEach(axis => {
- if (crop[axis] > border[axis] * (scale - 1)) {
- crop[axis] = border[axis] * (scale - 1);
+ if (crop[axis] > border[axis] * scale - canvas[axis]) {
+ crop[axis] = border[axis] * scale - canvas[axis]; // max bound
}
if (crop[axis] < 0) {
- crop[axis] = 0;
+ crop[axis] = 0; // min bound
}
});
imgselect.style.left = -crop[0]+'px';
imgselect.style.top = -crop[1]+'px';
imgselect.style.width = (scale * 100)+'%';
cropinput.value = [
- crop[0] / border[0], crop[1] / border[1],
- crop[0] / border[0] + 1, crop[1] / border[1] + 1,
+ crop[0] / border[0],
+ crop[1] / border[1],
+ (crop[0] + canvas[0]) / border[0],
+ (crop[1] + canvas[1]) / border[1],
].map(pos => Math.round(1000 * pos / scale));
}
function cropzoom(delta) {
- if (scale + delta < 1) {
- delta = 1 - scale; // scale = 1
+ if (scale + delta < minscale) {
+ delta = minscale - scale; // scale = 1
}
[0, 1].forEach(axis => {
// same area center at altered scale
imgselect.src = imgpreview.src;
imgselect.style.cursor = 'grab';
imgselect.style.position = 'absolute';
+ imgselect.style.maxWidth = 'none';
recrop();
imgselect.ontouchstart =