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odysseus/static/js/editor/tools/transform-drag.js
T

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JavaScript

/**
* Transform-drag tool — handle drag interactions for the Transform
* tool (resize via corner/edge handles, rotation via the rot grip).
*
* The transform UI runs in TWO modes: the floating popup (W/H/rot
* numeric inputs, lives elsewhere) AND direct drag on the canvas
* handles. Both ultimately mutate `state.transformPendingW/H/Rot` and
* call `reapplyTransform()` to redraw. This module owns the drag
* branch.
*
* The dispatcher in galleryEditor.js calls `tryBegin/tryContinue/
* tryEnd` which return `true` when the event was for the transform
* tool and was handled (so the dispatcher can short-circuit).
*
* @param {{
* composite: () => void,
* drawTransformHandles: () => void,
* reapplyTransform: () => void,
* getTransformHandle: (x: number, y: number) => string | null,
* cursorForHandle: (id: string | null) => string,
* pointInTransformFrame: (x: number, y: number) => boolean,
* snapTransformFrame?: (frame: object, center: {x:number,y:number}) => object,
* }} deps
*/
import { state } from '../state.js';
import { canvasCoords } from '../canvas-coords.js';
import { resizeTransformFrame } from '../transform-frame-geometry.js';
import { createDirectManipulationSession } from '../direct-manipulation-session.js';
export function createTransformDragTool({
composite, drawTransformHandles, reapplyTransform,
getTransformHandle, cursorForHandle, pointInTransformFrame,
snapTransformFrame,
}) {
const gesture = createDirectManipulationSession({
name: 'transform-frame',
getContext: () => ({ canvas: state.mainCanvas, items: state.transformItems }),
isContextCurrent: context => state.transformActive &&
context.canvas === state.mainCanvas && context.items === state.transformItems,
onCancel: () => {
state.transformHandle = null;
state.activeSnapGuides = null;
composite();
drawTransformHandles();
},
});
return {
/**
* Called on pointerdown. Returns true if the transform tool handled
* the event (the dispatcher should NOT fall through to other tools).
*/
tryBegin(e) {
if (!state.transformActive) return false;
const coords = canvasCoords(e, state.mainCanvas);
const pointerType = e.pointerType || (e.touches ? 'touch' : 'mouse');
state.transformHandle = getTransformHandle(coords.x, coords.y, { pointerType });
if (state.transformHandle) {
state.transformStartX = coords.x;
state.transformStartY = coords.y;
// Snapshot offset + size at drag-start so each frame computes
// "start + dx" (correct delta) rather than accumulating off the
// running offset, which was making top/left grabs drift.
const center = state.transformCenter || { x: 0, y: 0 };
state.transformStartCenter = { ...center };
state.transformOrigW = state.transformPendingW;
state.transformOrigH = state.transformPendingH;
state.transformStartRotation = state.transformPendingRot;
state.transformStartFlipH = state.transformPendingFlipH;
state.transformStartFlipV = state.transformPendingFlipV;
state.transformStartOffX = center.x - state.transformOrigW / 2;
state.transformStartOffY = center.y - state.transformOrigH / 2;
gesture.begin(e, { handle: state.transformHandle }, { captureTarget: e.currentTarget });
return true;
}
// No handle hit: dragging inside the staged frame moves the transform
// itself. Keeping this in the transform session is essential for
// selection transforms, which must never fall through to layer Move.
if (pointInTransformFrame?.(coords.x, coords.y)) {
state.transformHandle = 'move';
state.transformStartX = coords.x;
state.transformStartY = coords.y;
state.transformStartCenter = { ...(state.transformCenter || { x: 0, y: 0 }) };
gesture.begin(e, { handle: 'move' }, { captureTarget: e.currentTarget });
return true;
}
return false;
},
/**
* Called on pointermove. Returns true if handled.
*
* When transformActive but no handle is grabbed, updates the
* hover cursor + pulse. When a handle is grabbed, drives the
* resize / rotation pipeline.
*/
tryContinue(e) {
if (!state.transformActive) return false;
// No drag in progress — just hover-cursor + pulse.
if (!state.transformHandle && state.mainCanvas) {
const coords = canvasCoords(e, state.mainCanvas);
const pointerType = e.pointerType || (e.touches ? 'touch' : 'mouse');
const hovered = getTransformHandle(coords.x, coords.y, { pointerType });
const bodyHovered = !hovered && pointInTransformFrame?.(coords.x, coords.y);
state.mainCanvas.style.cursor = hovered
? cursorForHandle(hovered, state.transformPendingRot)
: bodyHovered ? 'move' : 'default';
if (hovered !== state.hoveredHandle) {
state.hoveredHandle = hovered;
composite();
}
return false; // didn't fully consume the event
}
if (!state.transformHandle) return false;
if (!gesture.update(e)) return false;
e.preventDefault();
const coords = canvasCoords(e, state.mainCanvas);
if (state.transformHandle === 'move') {
let center = {
x: state.transformStartCenter.x + coords.x - state.transformStartX,
y: state.transformStartCenter.y + coords.y - state.transformStartY,
};
const modifier = e.ctrlKey || e.metaKey;
const snapping = state.snapEnabled ? !modifier : modifier;
if (snapping && snapTransformFrame) {
const snapped = snapTransformFrame({
centerX: state.transformStartCenter.x,
centerY: state.transformStartCenter.y,
width: state.transformPendingW,
height: state.transformPendingH,
rotation: state.transformPendingRot,
}, center);
center = { x: snapped.centerX, y: snapped.centerY };
state.activeSnapGuides = snapped.guides || null;
} else {
state.activeSnapGuides = null;
}
state.transformCenter = center;
reapplyTransform();
return true;
}
// Rotation grip — angle measured from the layer's geometric
// centre to the cursor. Mirror into the popup if it's open.
if (state.transformHandle === 'rot') {
const cx = state.transformCenter?.x || 0;
const cy = state.transformCenter?.y || 0;
const rad = Math.atan2(coords.y - cy, coords.x - cx) + Math.PI / 2;
let deg = Math.round((rad * 180) / Math.PI);
if (e.shiftKey) deg = Math.round(deg / 15) * 15; // 15° snap
while (deg > 180) deg -= 360;
while (deg <= -180) deg += 360;
state.transformPendingRot = deg;
reapplyTransform();
if (state.transformPopup) {
const rotIn = state.transformPopup.querySelector('#ge-transform-rot');
if (rotIn) rotIn.value = String(deg);
}
return true;
}
// Resize in the frame's LOCAL axes. This keeps rotated side handles
// attached to the pointer and fixes the opposite edge in document space.
const resized = resizeTransformFrame({
centerX: state.transformStartCenter.x,
centerY: state.transformStartCenter.y,
width: state.transformOrigW,
height: state.transformOrigH,
rotation: state.transformStartRotation,
}, state.transformHandle, {
x: state.transformStartX,
y: state.transformStartY,
}, coords, {
centered: !!e.altKey,
lockAspect: !!e.shiftKey,
flipH: state.transformStartFlipH,
flipV: state.transformStartFlipV,
});
state.transformPendingW = resized.width;
state.transformPendingH = resized.height;
state.transformPendingFlipH = resized.flipH;
state.transformPendingFlipV = resized.flipV;
state.transformCenter = { x: resized.centerX, y: resized.centerY };
reapplyTransform();
// Mirror the new W/H into the popup if it's open.
if (state.transformPopup) {
const wIn = state.transformPopup.querySelector('#ge-transform-w');
const hIn = state.transformPopup.querySelector('#ge-transform-h');
if (wIn) wIn.value = String(state.transformPendingFlipH ? -resized.width : resized.width);
if (hIn) hIn.value = String(state.transformPendingFlipV ? -resized.height : resized.height);
}
return true;
},
/**
* Called on pointerup. Returns true if handled.
*/
tryEnd(e) {
if (!(state.transformActive && state.transformHandle)) return false;
if (!gesture.commit(e)) return false;
state.transformHandle = null;
state.transformOrigW = state.transformPendingW;
state.transformOrigH = state.transformPendingH;
state.activeSnapGuides = null;
composite();
drawTransformHandles();
return true;
},
cancel(reason) {
return gesture.cancel(reason);
},
};
}