Files
odysseus/static/js/editor/tools/transform-handles.js
T

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JavaScript

/**
* Transform-tool handle rendering + hit-testing + overlay sync.
*
* Lives separately from `transform-drag.js` (which owns the drag
* STATE MACHINE) because these three helpers are pure geometry that
* happens to read shared state — they don't track in-progress drags,
* they just paint and hit-test.
*
* - `syncOverlay(margin)` positions the overlay canvas + sizes its
* bitmap based on the main canvas + zoom.
* - `drawHandles(margin)` draws the rotated bounding outline + 8
* resize handles + the rotation knob (with
* hover / active visual states).
* - `getHandleAt(x, y)` returns the handle id under (x, y), or
* null. Geometry MUST mirror `drawHandles`
* exactly or the user grabs phantom points.
*
* No event listeners attached here — the dispatcher in
* editor/tools/transform-drag.js calls `getHandleAt` and routes
* pointer events.
*/
import { state } from '../state.js';
import {
hitTestTransformHandle,
pointInTransformFrame,
transformFrameGeometry,
} from '../transform-frame-geometry.js';
/**
* Position the transform overlay canvas + size its backing bitmap.
* Margin is screen-space slack on each side so controls remain visible
* at every zoom. It is converted to image pixels for the backing canvas.
*/
export function syncOverlay(margin) {
if (!state.transformOverlay || !state.mainCanvas) return;
if (!state.transformActive) {
state.transformOverlay.style.display = 'none';
return;
}
const imageMargin = margin / Math.max(0.0001, state.zoom);
const W = Math.ceil(state.mainCanvas.width + 2 * imageMargin);
const H = Math.ceil(state.mainCanvas.height + 2 * imageMargin);
if (state.transformOverlay.width !== W) state.transformOverlay.width = W;
if (state.transformOverlay.height !== H) state.transformOverlay.height = H;
// Overlay must scale with state.zoom so its handles render at the
// SAME on-screen size as the main canvas content. Without this, the
// overlay renders at full bitmap size while main canvas shrinks
// (zoomed-out), making handles look massive.
state.transformOverlay.style.display = '';
state.transformOverlay.style.position = 'absolute';
state.transformOverlay.style.width = (W * state.zoom) + 'px';
state.transformOverlay.style.height = (H * state.zoom) + 'px';
state.transformOverlay.style.pointerEvents = 'none';
state.transformOverlay.style.zIndex = '5';
// Position the overlay at the main canvas's LAYOUT position
// (offsetLeft/Top — unaffected by CSS transforms), shifted up-left by
// the overlay's `margin` image-px of handle slack. Then SHARE the
// canvas's transform (the pan handler writes the same translate3d to
// both canvas + overlay), so pan moves them together. Reading the
// layout offset (not getBoundingClientRect, which includes the pan
// transform) is what avoids the double-pan "bounce".
state.transformOverlay.style.left = Math.round(state.mainCanvas.offsetLeft - margin) + 'px';
state.transformOverlay.style.top = Math.round(state.mainCanvas.offsetTop - margin) + 'px';
state.transformOverlay.style.transform = state.mainCanvas.style.transform || 'none';
}
function rotationHandleInside(frame) {
let inside = false;
const outside = transformFrameGeometry(frame, { zoom: state.zoom }).rotationHandle;
// The overlay deliberately extends beyond the image, so only fold the
// rotation control inward when the surrounding viewport would clip it.
try {
const area = state.container && state.container.querySelector('.ge-canvas-area');
if (area && !inside) {
const aRect = area.getBoundingClientRect();
const mRect = state.mainCanvas.getBoundingClientRect();
const scaleX = mRect.width / state.mainCanvas.width;
const scaleY = mRect.height / state.mainCanvas.height;
const knobClientX = mRect.left + outside.x * scaleX;
const knobClientY = mRect.top + outside.y * scaleY;
if (knobClientY < aRect.top + 6) inside = true;
if (knobClientX < aRect.left + 6 || knobClientX > aRect.right - 6) inside = true;
const popupRect = state.transformPopup?.getBoundingClientRect?.();
if (popupRect
&& knobClientX >= popupRect.left
&& knobClientX <= popupRect.right
&& knobClientY >= popupRect.top
&& knobClientY <= popupRect.bottom) {
inside = true;
}
}
} catch {}
return inside;
}
function transformFrame() {
if (state.transformTarget === 'selection') {
if (!state.transformSelectionBounds) return null;
return {
centerX: state.transformCenter?.x ?? state.transformSelectionBounds.centerX,
centerY: state.transformCenter?.y ?? state.transformSelectionBounds.centerY,
width: state.transformPendingW || state.transformSelectionBounds.width,
height: state.transformPendingH || state.transformSelectionBounds.height,
rotation: state.transformPendingRot || 0,
};
}
const layer = state.transformLayer;
if (!layer) return null;
const off = state.layerOffsets.get(layer.id) || { x: 0, y: 0 };
const fallbackCenter = {
x: off.x + layer.canvas.width / 2,
y: off.y + layer.canvas.height / 2,
};
return {
centerX: state.transformCenter?.x ?? fallbackCenter.x,
centerY: state.transformCenter?.y ?? fallbackCenter.y,
width: state.transformPendingW || layer.canvas.width,
height: state.transformPendingH || layer.canvas.height,
rotation: state.transformPendingRot || 0,
};
}
/**
* Draw the rotated bounding outline + 8 resize handles + the rotation
* knob into the overlay canvas. The overlay is translated by `margin`
* so image (0,0) maps to overlay (margin, margin).
*/
export function drawHandles(margin) {
if (!state.transformActive || (state.transformTarget !== 'selection' && !state.transformLayer)) return;
syncOverlay(margin);
if (!state.transformOverlayCtx) return;
const frame = transformFrame();
if (!frame) return;
const rotInside = rotationHandleInside(frame);
const geometry = transformFrameGeometry(frame, {
zoom: state.zoom,
rotationInside: rotInside,
});
const ctx = state.transformOverlayCtx;
const accent = getComputedStyle(document.documentElement).getPropertyValue('--accent').trim() || '#e06c75';
const imageMargin = margin / Math.max(0.0001, state.zoom);
// Clear + shift drawing by margin so image (0,0) maps to overlay (M,M).
ctx.clearRect(0, 0, state.transformOverlay.width, state.transformOverlay.height);
ctx.save();
ctx.translate(imageMargin, imageMargin);
// Zoom-corrected handle size + stroke so they stay readable at any zoom.
const sz = 10 / state.zoom;
const stroke = 1.5 / state.zoom;
const { tl, tr, br, bl } = geometry.corners;
// Use the editor accent instead of white so the frame remains distinct
// from both the canvas and the ruler/UI chrome.
const drawRectOutline = () => {
ctx.beginPath();
ctx.moveTo(tl.x, tl.y);
ctx.lineTo(tr.x, tr.y);
ctx.lineTo(br.x, br.y);
ctx.lineTo(bl.x, bl.y);
ctx.closePath();
ctx.stroke();
};
ctx.lineWidth = 3 / state.zoom;
ctx.strokeStyle = 'rgba(0, 0, 0, 0.82)';
ctx.setLineDash([6 / state.zoom, 4 / state.zoom]);
ctx.lineDashOffset = 1 / state.zoom;
drawRectOutline();
ctx.lineWidth = 1.5 / state.zoom;
ctx.strokeStyle = getComputedStyle(document.documentElement).getPropertyValue('--accent').trim() || '#e06c75';
ctx.lineDashOffset = 0;
drawRectOutline();
ctx.setLineDash([]);
// Resize handles + rotation knob anchored to the rotated layer's
// top-center (not bbox top), so the knob stays attached to the
// visible content as it spins.
const topHandle = geometry.resizeHandles.find(handle => handle.id === 't');
if (!rotInside) {
ctx.beginPath();
ctx.moveTo(topHandle.x, topHandle.y);
ctx.lineTo(geometry.rotationHandle.x, geometry.rotationHandle.y);
ctx.strokeStyle = accent;
ctx.lineWidth = 1 / state.zoom;
ctx.stroke();
}
for (const c of geometry.handles) {
const active = c.id === state.transformHandle;
const hovered = !active && c.id === state.hoveredHandle;
const edge = c.id.length === 1 && c.id !== 'rot';
const baseRadius = edge ? sz * 0.42 : sz / 2;
const radius = active ? sz * 0.75 : hovered ? sz * 0.6 : baseRadius;
ctx.beginPath();
ctx.arc(c.x, c.y, radius, 0, Math.PI * 2);
ctx.fillStyle = active ? '#fff' : hovered ? '#ffd' : accent;
ctx.fill();
ctx.lineWidth = stroke;
ctx.strokeStyle = active ? accent : 'rgba(0, 0, 0, 0.72)';
ctx.stroke();
if (hovered) {
// Subtle red ring around the hovered handle for visual feedback.
ctx.beginPath();
ctx.arc(c.x, c.y, radius + 2 / state.zoom, 0, Math.PI * 2);
ctx.strokeStyle = 'rgba(224, 108, 117, 0.7)';
ctx.lineWidth = stroke;
ctx.stroke();
}
}
// The center marker communicates the rotation pivot without becoming an
// interactive handle until pivot dragging lands in the transform workflow.
const pivotRadius = 3 / state.zoom;
ctx.beginPath();
ctx.arc(geometry.pivot.x, geometry.pivot.y, pivotRadius, 0, Math.PI * 2);
ctx.strokeStyle = accent;
ctx.lineWidth = 1 / state.zoom;
ctx.stroke();
ctx.restore();
}
/**
* Hit-test (x, y) against the transform handles. Returns the handle
* id ('tl' | 't' | 'tr' | 'r' | 'br' | 'b' | 'bl' | 'l' | 'rot') or null.
*
* Geometry MUST mirror `drawHandles` exactly, otherwise the user
* grabs phantom points.
*/
export function getHandleAt(x, y, options = {}) {
if (state.transformTarget !== 'selection' && !state.transformLayer) return null;
const frame = transformFrame();
if (!frame) return null;
const rotationInside = rotationHandleInside(frame);
const geometry = transformFrameGeometry(frame, {
zoom: state.zoom,
rotationInside,
});
const hit = hitTestTransformHandle(geometry, x, y, {
zoom: state.zoom,
pointerType: options.pointerType,
});
if (hit || !rotationInside) return hit;
// Keep the clipped grip reachable during viewport-edge transitions. The
// frame is drawn with the inward position, but a touch can begin from the
// previously rendered outward position for one frame after a resize/pan.
const unclippedGeometry = transformFrameGeometry(frame, {
zoom: state.zoom,
rotationInside: false,
});
return hitTestTransformHandle(unclippedGeometry, x, y, {
zoom: state.zoom,
pointerType: options.pointerType,
});
}
/** True only for the visible rotated frame, not its empty AABB corners. */
export function containsFramePoint(x, y) {
const frame = transformFrame();
if (!frame) return false;
return pointInTransformFrame(transformFrameGeometry(frame, { zoom: state.zoom }), x, y);
}