272 lines
11 KiB
JavaScript
272 lines
11 KiB
JavaScript
/**
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* Transform-tool handle rendering + hit-testing + overlay sync.
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*
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* Lives separately from `transform-drag.js` (which owns the drag
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* STATE MACHINE) because these three helpers are pure geometry that
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* happens to read shared state — they don't track in-progress drags,
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* they just paint and hit-test.
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*
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* - `syncOverlay(margin)` positions the overlay canvas + sizes its
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* bitmap based on the main canvas + zoom.
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* - `drawHandles(margin)` draws the rotated bounding outline + 4
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* corner handles + the rotation knob (with
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* hover / active visual states).
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* - `getHandleAt(x, y)` returns the handle id under (x, y), or
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* null. Geometry MUST mirror `drawHandles`
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* exactly or the user grabs phantom points.
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*
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* No event listeners attached here — the dispatcher in
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* editor/tools/transform-drag.js calls `getHandleAt` and routes
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* pointer events.
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*/
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import { state } from '../state.js';
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/**
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* Position the transform overlay canvas + size its backing bitmap.
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* Margin is the image-space slack each side so handles can render
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* outside the main canvas (matches _TRANSFORM_OVERLAY_MARGIN in
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* galleryEditor.js — kept as a parameter so this module has no
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* dependency on a magic number defined elsewhere).
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*/
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export function syncOverlay(margin) {
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if (!state.transformOverlay || !state.mainCanvas) return;
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if (!state.transformActive) {
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state.transformOverlay.style.display = 'none';
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return;
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}
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const W = state.mainCanvas.width + 2 * margin;
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const H = state.mainCanvas.height + 2 * margin;
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if (state.transformOverlay.width !== W) state.transformOverlay.width = W;
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if (state.transformOverlay.height !== H) state.transformOverlay.height = H;
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// Overlay must scale with state.zoom so its handles render at the
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// SAME on-screen size as the main canvas content. Without this, the
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// overlay renders at full bitmap size while main canvas shrinks
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// (zoomed-out), making handles look massive.
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state.transformOverlay.style.display = '';
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state.transformOverlay.style.position = 'absolute';
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state.transformOverlay.style.width = (W * state.zoom) + 'px';
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state.transformOverlay.style.height = (H * state.zoom) + 'px';
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state.transformOverlay.style.pointerEvents = 'none';
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state.transformOverlay.style.zIndex = '5';
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// Position the overlay at the main canvas's LAYOUT position
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// (offsetLeft/Top — unaffected by CSS transforms), shifted up-left by
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// the overlay's `margin` image-px of handle slack. Then SHARE the
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// canvas's transform (the pan handler writes the same translate3d to
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// both canvas + overlay), so pan moves them together. Reading the
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// layout offset (not getBoundingClientRect, which includes the pan
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// transform) is what avoids the double-pan "bounce".
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state.transformOverlay.style.left = Math.round(state.mainCanvas.offsetLeft - margin * state.zoom) + 'px';
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state.transformOverlay.style.top = Math.round(state.mainCanvas.offsetTop - margin * state.zoom) + 'px';
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state.transformOverlay.style.transform = state.mainCanvas.style.transform || 'none';
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}
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/**
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* Compute the on-screen position of the rotation knob given the
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* layer's bbox center + rotation. The knob normally sits OUTSIDE the
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* top edge of the rotated layer; if that would land beyond the canvas
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* viewport, flip it INSIDE.
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*
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* Returned by `_knobPosition` and shared by drawHandles + getHandleAt
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* so both compute the same point.
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*/
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function knobPosition(cxh, cyh, rotRad, baseInnerR, rotOffset) {
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let rotInside = false;
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const outsideR = baseInnerR + rotOffset;
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const knobLocalX = cxh + Math.sin(rotRad) * outsideR;
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const knobLocalY = cyh - Math.cos(rotRad) * outsideR;
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// Primary check: anything drawn outside the main canvas's pixel
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// buffer is invisible (canvas operations clip silently).
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if (
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knobLocalX < 0 || knobLocalY < 0 ||
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knobLocalX > state.mainCanvas.width || knobLocalY > state.mainCanvas.height
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) {
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rotInside = true;
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}
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// Secondary check: even if the knob is inside the canvas bitmap, the
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// viewport may have scrolled the canvas such that the knob falls
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// outside the visible canvas-area window.
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try {
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const area = state.container && state.container.querySelector('.ge-canvas-area');
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if (area && !rotInside) {
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const aRect = area.getBoundingClientRect();
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const mRect = state.mainCanvas.getBoundingClientRect();
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const scaleX = mRect.width / state.mainCanvas.width;
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const scaleY = mRect.height / state.mainCanvas.height;
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const knobClientX = mRect.left + knobLocalX * scaleX;
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const knobClientY = mRect.top + knobLocalY * scaleY;
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if (knobClientY < aRect.top + 6) rotInside = true;
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if (knobClientX < aRect.left + 6 || knobClientX > aRect.right - 6) rotInside = true;
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}
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} catch {}
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const innerR = rotInside ? Math.max(4, baseInnerR - rotOffset) : baseInnerR;
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const rotR = rotInside ? innerR : baseInnerR + rotOffset;
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return {
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rotInside,
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innerR,
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rotX: cxh + Math.sin(rotRad) * rotR,
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rotY: cyh - Math.cos(rotRad) * rotR,
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};
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}
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/**
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* Draw the rotated bounding outline + 4 corner handles + the rotation
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* knob into the overlay canvas. The overlay is translated by `margin`
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* so image (0,0) maps to overlay (margin, margin).
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*/
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export function drawHandles(margin) {
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if (!state.transformActive || !state.transformLayer) return;
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syncOverlay(margin);
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if (!state.transformOverlayCtx) return;
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const layer = state.transformLayer;
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const off = state.layerOffsets.get(layer.id) || { x: 0, y: 0 };
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const w = layer.canvas.width;
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const h = layer.canvas.height;
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const ctx = state.transformOverlayCtx;
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// Clear + shift drawing by margin so image (0,0) maps to overlay (M,M).
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ctx.clearRect(0, 0, state.transformOverlay.width, state.transformOverlay.height);
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ctx.save();
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ctx.translate(margin, margin);
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// Zoom-corrected handle size + stroke so they stay readable at any zoom.
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const sz = 10 / state.zoom;
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const stroke = 1.5 / state.zoom;
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// Pre-rotation rectangle dims (what the user sees the layer as).
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// Falls back to layer bbox before any popup values exist.
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const preW = state.transformPendingW || w;
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const preH = state.transformPendingH || h;
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const cxBox = off.x + w / 2;
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const cyBox = off.y + h / 2;
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const rotRadBox = ((state.transformPendingRot || 0) * Math.PI) / 180;
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const cosBox = Math.cos(rotRadBox);
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const sinBox = Math.sin(rotRadBox);
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const rotPt = (dx, dy) => ({
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x: cxBox + dx * cosBox - dy * sinBox,
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y: cyBox + dx * sinBox + dy * cosBox,
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});
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const tl = rotPt(-preW / 2, -preH / 2);
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const tr = rotPt( preW / 2, -preH / 2);
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const br = rotPt( preW / 2, preH / 2);
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const bl = rotPt(-preW / 2, preH / 2);
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// Outline of the rotated rectangle — solid white inner line with a
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// thin black halo for contrast on light AND dark backgrounds.
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const drawRectOutline = () => {
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ctx.beginPath();
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ctx.moveTo(tl.x, tl.y);
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ctx.lineTo(tr.x, tr.y);
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ctx.lineTo(br.x, br.y);
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ctx.lineTo(bl.x, bl.y);
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ctx.closePath();
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ctx.stroke();
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};
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ctx.lineWidth = 1 / state.zoom;
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ctx.strokeStyle = 'rgba(0, 0, 0, 0.45)';
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ctx.setLineDash([6 / state.zoom, 4 / state.zoom]);
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ctx.lineDashOffset = 1 / state.zoom;
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drawRectOutline();
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ctx.strokeStyle = '#fff';
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ctx.lineDashOffset = 0;
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drawRectOutline();
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ctx.setLineDash([]);
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// Corner handles + rotation knob anchored to the rotated layer's
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// top-center (not bbox top), so the knob stays attached to the
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// visible content as it spins.
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const rotOffset = 24 / state.zoom;
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const cxh = off.x + w / 2;
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const cyh = off.y + h / 2;
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const rotRad = ((state.transformPendingRot || 0) * Math.PI) / 180;
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const baseInnerR = (state.transformPendingH || h) / 2;
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const knob = knobPosition(cxh, cyh, rotRad, baseInnerR, rotOffset);
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// Tether line collapses to a point when knob is inside the layer.
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const drawTether = !knob.rotInside;
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const innerX = cxh + Math.sin(rotRad) * baseInnerR;
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const innerY = cyh - Math.cos(rotRad) * baseInnerR;
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const corners = [
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{ x: tl.x, y: tl.y, id: 'tl' },
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{ x: tr.x, y: tr.y, id: 'tr' },
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{ x: br.x, y: br.y, id: 'br' },
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{ x: bl.x, y: bl.y, id: 'bl' },
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{ x: knob.rotX, y: knob.rotY, id: 'rot' },
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];
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if (drawTether) {
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ctx.beginPath();
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ctx.moveTo(innerX, innerY);
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ctx.lineTo(knob.rotX, knob.rotY);
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ctx.strokeStyle = 'rgba(255, 255, 255, 0.7)';
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ctx.lineWidth = 1 / state.zoom;
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ctx.stroke();
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}
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for (const c of corners) {
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const active = c.id === state.transformHandle;
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const hovered = !active && c.id === state.hoveredHandle;
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const radius = (active ? sz * 0.75 : hovered ? sz * 0.6 : sz / 2);
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ctx.beginPath();
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ctx.arc(c.x, c.y, radius, 0, Math.PI * 2);
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ctx.fillStyle = active ? '#e06c75' : hovered ? '#ffd' : '#fff';
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ctx.fill();
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ctx.lineWidth = stroke;
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ctx.strokeStyle = active ? '#fff' : 'rgba(0, 0, 0, 0.5)';
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ctx.stroke();
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if (hovered) {
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// Subtle red ring around the hovered handle for visual feedback.
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ctx.beginPath();
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ctx.arc(c.x, c.y, radius + 2 / state.zoom, 0, Math.PI * 2);
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ctx.strokeStyle = 'rgba(224, 108, 117, 0.7)';
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ctx.lineWidth = stroke;
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ctx.stroke();
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}
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}
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ctx.restore();
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}
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/**
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* Hit-test (x, y) against the transform handles. Returns the handle
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* id ('tl' | 'tr' | 'br' | 'bl' | 'rot') or null.
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*
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* Geometry MUST mirror `drawHandles` exactly, otherwise the user
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* grabs phantom points.
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*/
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export function getHandleAt(x, y) {
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if (!state.transformLayer) return null;
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const layer = state.transformLayer;
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const off = state.layerOffsets.get(layer.id) || { x: 0, y: 0 };
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const w = layer.canvas.width;
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const h = layer.canvas.height;
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const threshold = 8 / state.zoom;
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const rotOffset = 24 / state.zoom;
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const cxh = off.x + w / 2;
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const cyh = off.y + h / 2;
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const rotRad = ((state.transformPendingRot || 0) * Math.PI) / 180;
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const baseInnerR = (state.transformPendingH || h) / 2;
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const knob = knobPosition(cxh, cyh, rotRad, baseInnerR, rotOffset);
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// Rotate corners around centre — must match drawHandles.
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const preW = state.transformPendingW || w;
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const preH = state.transformPendingH || h;
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const cosA = Math.cos(rotRad);
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const sinA = Math.sin(rotRad);
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const rotCorner = (dx, dy) => ({
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x: cxh + dx * cosA - dy * sinA,
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y: cyh + dx * sinA + dy * cosA,
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});
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const tlH = rotCorner(-preW / 2, -preH / 2);
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const trH = rotCorner( preW / 2, -preH / 2);
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const brH = rotCorner( preW / 2, preH / 2);
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const blH = rotCorner(-preW / 2, preH / 2);
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const handles = [
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{ x: tlH.x, y: tlH.y, id: 'tl' },
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{ x: trH.x, y: trH.y, id: 'tr' },
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{ x: brH.x, y: brH.y, id: 'br' },
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{ x: blH.x, y: blH.y, id: 'bl' },
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{ x: knob.rotX, y: knob.rotY, id: 'rot' },
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];
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for (const c of handles) {
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if (Math.abs(x - c.x) < threshold && Math.abs(y - c.y) < threshold) return c.id;
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}
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return null;
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}
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