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Improve canvas overlay rendering #48

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613bcd2
fix canvas overlay rendering
Udhul Jun 26, 2025
fd02cf9
fix overlay redraw and remove prediction caching
Udhul Jun 26, 2025
7893516
fix overlay mask alignment with zoom
Udhul Jun 26, 2025
29ce7c0
Fix overlay cropping by scaling offscreen canvases
Udhul Jun 26, 2025
55753f6
fix: align overlay cropping with zoom
Udhul Jun 26, 2025
f48f68e
fix overlay transform order
Udhul Jun 26, 2025
5023349
fix overlay cropping with correct transform order
Udhul Jun 27, 2025
8924399
fix overlay transform
Udhul Jun 27, 2025
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153 changes: 83 additions & 70 deletions app/frontend/static/js/canvasController.js
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Original file line number Diff line number Diff line change
Expand Up @@ -205,15 +205,25 @@ class CanvasManager {
// It will be resized in drawPredictionMaskLayer if needed.
}

// Offscreen canvases match the base display size of the image. They are not
// resized on zoom to avoid cropping issues when panning. They will be sized
// in `drawImageLayer` whenever the image or display area changes.

applyCanvasTransform() {
const t = `translate(${this.transform.panX}px, ${this.transform.panY}px) scale(${this.transform.scale})`;
[this.imageCanvas, this.predictionMaskCanvas, this.userInputCanvas].forEach(c => {
if (c) {
c.style.transformOrigin = 'top left';
c.style.transform = t;
}
});
const t = `scale(${this.transform.scale}) translate(${this.transform.panX}px, ${this.transform.panY}px)`;
if (this.imageCanvas) {
this.imageCanvas.style.transformOrigin = 'top left';
this.imageCanvas.style.transform = t;
}
if (this.predictionMaskCanvas) {
this.predictionMaskCanvas.style.transform = 'none';
}
if (this.userInputCanvas) {
this.userInputCanvas.style.transform = 'none';
}
this._dispatchEvent('zoom-pan-changed', { scale: this.transform.scale, panX: this.transform.panX, panY: this.transform.panY });
this.drawUserInputLayer();
this.drawPredictionMaskLayer();
}

// --- Coordinate Transformation ---
Expand All @@ -222,24 +232,28 @@ class CanvasManager {
this.userInputCanvas.width === 0 || this.userInputCanvas.height === 0) return { x: 0, y: 0 };

const rect = this.userInputCanvas.getBoundingClientRect();
// Normalize click coordinates to be relative to the canvas element
const canvasX = (clientX - rect.left) * (this.userInputCanvas.width / rect.width);
const canvasY = (clientY - rect.top) * (this.userInputCanvas.height / rect.height);

// Scale canvas coordinates to original image coordinates
const scale = this.displayScale * this.transform.scale;
return {
x: canvasX / this.displayScale,
y: canvasY / this.displayScale
x: (canvasX - this.transform.panX) / scale,
y: (canvasY - this.transform.panY) / scale
};
}

_originalToViewportCoords(originalX, originalY) {
if (!this.originalImageWidth || !this.originalImageHeight || !this.userInputCanvas ||
this.userInputCanvas.width === 0 || this.userInputCanvas.height === 0) return { x: 0, y: 0 };
const scale = this.displayScale;
return { x: originalX * scale, y: originalY * scale };
}

_originalToDisplayCoords(originalX, originalY) {
if (!this.originalImageWidth || !this.originalImageHeight || !this.userInputCanvas ||
this.userInputCanvas.width === 0 || this.userInputCanvas.height === 0) return { x: 0, y: 0 };
return {
x: originalX * this.displayScale,
y: originalY * this.displayScale
};
const pv = this._originalToViewportCoords(originalX, originalY);
return { x: pv.x + this.transform.panX, y: pv.y + this.transform.panY };
}

getZoomedDisplayScale() {
Expand Down Expand Up @@ -431,17 +445,17 @@ class CanvasManager {

this.offscreenUserCtx.clearRect(0, 0, this.offscreenUserCanvas.width, this.offscreenUserCanvas.height);

const pointDisplayRadius = Math.max(2, 5 * this.displayScale); // Scale point radius slightly
const lineDisplayWidth = Math.max(1, 2 * this.displayScale); // Scale line width
const pointDisplayRadius = Math.max(2, 5 * this.displayScale);
const lineDisplayWidth = Math.max(1, 2 * this.displayScale);

// Draw drawn polygons (lassos)
this.userDrawnMasks.forEach(mask => {
if (mask.points.length < 3) return;
this.offscreenUserCtx.beginPath();
const firstP_disp = this._originalToDisplayCoords(mask.points[0].x, mask.points[0].y);
const firstP_disp = this._originalToViewportCoords(mask.points[0].x, mask.points[0].y);
this.offscreenUserCtx.moveTo(firstP_disp.x, firstP_disp.y);
for (let i = 1; i < mask.points.length; i++) {
const p_disp = this._originalToDisplayCoords(mask.points[i].x, mask.points[i].y);
const p_disp = this._originalToViewportCoords(mask.points[i].x, mask.points[i].y);
this.offscreenUserCtx.lineTo(p_disp.x, p_disp.y);
}
this.offscreenUserCtx.closePath();
Expand All @@ -455,10 +469,10 @@ class CanvasManager {
// Draw current lasso drawing in progress
if (this.isDrawingLasso && this.currentLassoPoints.length > 0) {
this.offscreenUserCtx.beginPath();
const firstP_disp = this._originalToDisplayCoords(this.currentLassoPoints[0].x, this.currentLassoPoints[0].y);
const firstP_disp = this._originalToViewportCoords(this.currentLassoPoints[0].x, this.currentLassoPoints[0].y);
this.offscreenUserCtx.moveTo(firstP_disp.x, firstP_disp.y);
for (let i = 1; i < this.currentLassoPoints.length; i++) {
const p_disp = this._originalToDisplayCoords(this.currentLassoPoints[i].x, this.currentLassoPoints[i].y);
const p_disp = this._originalToViewportCoords(this.currentLassoPoints[i].x, this.currentLassoPoints[i].y);
this.offscreenUserCtx.lineTo(p_disp.x, p_disp.y);
}
this.offscreenUserCtx.strokeStyle = 'rgba(255, 223, 0, 0.95)';
Expand All @@ -468,7 +482,7 @@ class CanvasManager {

// Draw points
this.userPoints.forEach(p_orig => {
const dp = this._originalToDisplayCoords(p_orig.x, p_orig.y);
const dp = this._originalToViewportCoords(p_orig.x, p_orig.y);
this.offscreenUserCtx.beginPath();
this.offscreenUserCtx.arc(dp.x, dp.y, pointDisplayRadius, 0, 2 * Math.PI);
this.offscreenUserCtx.fillStyle = p_orig.label === 1 ? 'rgba(50, 205, 50, 0.8)' : 'rgba(255, 69, 0, 0.8)'; // LimeGreen/OrangeRed
Expand All @@ -481,8 +495,8 @@ class CanvasManager {
// Draw boxes
[...this.userBoxes, this.currentBox].forEach(box => {
if (!box) return;
const db1 = this._originalToDisplayCoords(box.x1, box.y1);
const db2 = this._originalToDisplayCoords(box.x2, box.y2);
const db1 = this._originalToViewportCoords(box.x1, box.y1);
const db2 = this._originalToViewportCoords(box.x2, box.y2);
this.offscreenUserCtx.strokeStyle = 'rgba(30, 144, 255, 0.85)'; // DodgerBlue
this.offscreenUserCtx.lineWidth = lineDisplayWidth;
this.offscreenUserCtx.strokeRect(db1.x, db1.y, db2.x - db1.x, db2.y - db1.y);
Expand All @@ -492,11 +506,15 @@ class CanvasManager {
this.offscreenUserCtx.strokeRect(db1.x, db1.y, db2.x - db1.x, db2.y - db1.y);
});

// Composite to visible canvas
// Composite to visible canvas using the current zoom/pan transform
this.userCtx.setTransform(1, 0, 0, 1, 0, 0);
this.userCtx.clearRect(0, 0, this.userInputCanvas.width, this.userInputCanvas.height);
this.userCtx.save();
this.userCtx.setTransform(this.transform.scale, 0, 0, this.transform.scale, this.transform.panX, this.transform.panY);
this.userCtx.globalAlpha = this.userInputOpacitySlider ? parseFloat(this.userInputOpacitySlider.value) : 0.8;
this.userCtx.imageSmoothingEnabled = false;
this.userCtx.drawImage(this.offscreenUserCanvas, 0, 0);
this.userCtx.globalAlpha = 1.0;
this.userCtx.restore();
}

drawPredictionMaskLayer() {
Expand All @@ -515,13 +533,10 @@ class CanvasManager {
if (this.mode === 'edit' && this.selectedLayerIds.length > 0) {
op = this.selectedLayerIds.includes(l.layerId) ? 1.0 : FADED_MASK_OPACITY;
}
const mask = (this.editingLayerId && l.layerId === this.editingLayerId && this.editingMask)
? this.editingMask
: l.maskData;
const color = (this.editingLayerId && l.layerId === this.editingLayerId)
? this.editingColor
: l.color;
if (mask) this._drawBinaryMask(mask, color, op);
const isEditing = this.editingLayerId && l.layerId === this.editingLayerId && this.editingMask;
const mask = isEditing ? this.editingMask : l.maskData;
const color = isEditing ? this.editingColor : l.color;
if (mask) this._drawBinaryMask(mask, color, op, isEditing);
});
}

Expand Down Expand Up @@ -574,21 +589,26 @@ class CanvasManager {

if (pixelCount > 0) {
this.tempMaskPixelCtx.putImageData(imageData, 0, 0);
// Draw the processed mask (at original resolution) onto the offscreen canvas,
// scaling it down to the display size.
this.offscreenPredictionCtx.drawImage(this.tempMaskPixelCanvas, 0, 0,
this.offscreenPredictionCanvas.width,
this.offscreenPredictionCanvas.height);
const scaledW = maskWidth * this.displayScale;
const scaledH = maskHeight * this.displayScale;
this.offscreenPredictionCtx.save();
this.offscreenPredictionCtx.imageSmoothingEnabled = false;
this.offscreenPredictionCtx.drawImage(this.tempMaskPixelCanvas, 0, 0, scaledW, scaledH);
this.offscreenPredictionCtx.restore();
}
});
}

// Composite to visible prediction canvas
// Composite to visible prediction canvas using the current transform
this.predictionCtx.setTransform(1, 0, 0, 1, 0, 0);
this.predictionCtx.clearRect(0, 0, this.predictionMaskCanvas.width, this.predictionMaskCanvas.height);
this.predictionCtx.save();
this.predictionCtx.setTransform(this.transform.scale, 0, 0, this.transform.scale, this.transform.panX, this.transform.panY);
const opacity = this.predictionOpacitySlider ? parseFloat(this.predictionOpacitySlider.value) : 0.7;
this.predictionCtx.globalAlpha = opacity;
this.predictionCtx.imageSmoothingEnabled = false;
this.predictionCtx.drawImage(this.offscreenPredictionCanvas, 0, 0);
this.predictionCtx.globalAlpha = 1.0;
this.predictionCtx.restore();
}

// --- User Interaction Handlers ---
Expand Down Expand Up @@ -750,8 +770,8 @@ class CanvasManager {
if (newScale > maxScale) newScale = maxScale;

const scaleRatio = newScale / prevScale;
this.transform.panX += offsetX * (1 - scaleRatio);
this.transform.panY += offsetY * (1 - scaleRatio);
this.transform.panX -= (offsetX - this.transform.panX) * (scaleRatio - 1);
this.transform.panY -= (offsetY - this.transform.panY) * (scaleRatio - 1);
this.transform.scale = newScale;

this._clampPan();
Expand Down Expand Up @@ -893,7 +913,7 @@ class CanvasManager {
}
}

_drawBinaryMask(maskData, colorStr, opacity = 1.0) {
_drawBinaryMask(maskData, colorStr, opacity = 1.0, solid = false) {
if (!maskData || !maskData.length || !maskData[0].length) return;
const maskHeight = maskData.length;
const maskWidth = maskData[0].length;
Expand All @@ -909,7 +929,7 @@ class CanvasManager {
const [r, g, b, a_int] = this._parseRgbaFromString(colorStr);
const finalAlpha = Math.round(Math.min(1, Math.max(0, opacity)) * a_int);

const spacing = 6; // pixel spacing between hatch lines
const spacing = solid ? 1 : 4; // pixel spacing between hatch lines
const lineWidth = 2; // hatch line thickness

const isBorder = (mx, my) => {
Expand All @@ -926,7 +946,7 @@ class CanvasManager {
if (!maskData[y][x]) continue;
const idx = (y * maskWidth + x) * 4;
const border = isBorder(x, y);
const drawPixel = border || ((x + y) % spacing < lineWidth);
const drawPixel = border || solid || ((x + y) % spacing < lineWidth);
if (drawPixel) {
pixelData[idx] = r;
pixelData[idx + 1] = g;
Expand All @@ -937,8 +957,14 @@ class CanvasManager {
}

this.tempMaskPixelCtx.putImageData(imageData, 0, 0);
this.offscreenPredictionCtx.drawImage(this.tempMaskPixelCanvas, 0, 0,
this.offscreenPredictionCanvas.width, this.offscreenPredictionCanvas.height);

const scaledW = maskWidth * this.displayScale;
const scaledH = maskHeight * this.displayScale;
this.offscreenPredictionCtx.save();
this.offscreenPredictionCtx.imageSmoothingEnabled = false;
this.offscreenPredictionCtx.globalAlpha = 1.0; // opacity baked in alpha
this.offscreenPredictionCtx.drawImage(this.tempMaskPixelCanvas, 0, 0, scaledW, scaledH);
this.offscreenPredictionCtx.restore();
}

_dispatchEvent(eventType, data) {
Expand Down Expand Up @@ -1067,37 +1093,24 @@ class CanvasManager {

exportState() {
return {
points: JSON.parse(JSON.stringify(this.userPoints)),
boxes: JSON.parse(JSON.stringify(this.userBoxes)),
drawnMasks: JSON.parse(JSON.stringify(this.userDrawnMasks)),
maskInput: this.combinedUserMaskInput256 ? JSON.parse(JSON.stringify(this.combinedUserMaskInput256)) : null,
manualPredictions: JSON.parse(JSON.stringify(this.manualPredictions)),
automaskPredictions: JSON.parse(JSON.stringify(this.automaskPredictions)),
selectedManualMaskIndex: this.selectedManualMaskIndex,
currentPredictionMultiBox: this.currentPredictionMultiBox,
layers: JSON.parse(JSON.stringify(this.layers)),
selectedLayerIds: JSON.parse(JSON.stringify(this.selectedLayerIds)),
mode: this.mode
mode: this.mode,
transform: { ...this.transform }
};
}

importState(state) {
if (!state) return;
this.userPoints = state.points || [];
this.userBoxes = state.boxes || [];
this.currentBox = null;
this.userDrawnMasks = state.drawnMasks || [];
this.combinedUserMaskInput256 = state.maskInput || null;
this.manualPredictions = state.manualPredictions || [];
this.automaskPredictions = state.automaskPredictions || [];
this.selectedManualMaskIndex = state.selectedManualMaskIndex || 0;
this.currentPredictionMultiBox = state.currentPredictionMultiBox || false;
this.layers = state.layers || [];
this.selectedLayerIds = state.selectedLayerIds || [];
this.mode = state.mode || 'edit';
if (this.userDrawnMasks.length > 0) this._prepareCombinedUserMaskInput();
this.drawUserInputLayer();
this.drawPredictionMaskLayer();
if (state.transform) {
this.transform = { ...this.transform, ...state.transform };
this.applyCanvasTransform();
} else {
this.drawPredictionMaskLayer();
}
}

startMaskEdit(layerId, maskData, color) {
Expand Down Expand Up @@ -1168,10 +1181,10 @@ class CanvasManager {
this.offscreenUserCtx.clearRect(0, 0, this.offscreenUserCanvas.width, this.offscreenUserCanvas.height);
if (points && points.length > 0) {
this.offscreenUserCtx.beginPath();
const first = this._originalToDisplayCoords(points[0].x, points[0].y);
const first = this._originalToViewportCoords(points[0].x, points[0].y);
this.offscreenUserCtx.moveTo(first.x, first.y);
for (let i = 1; i < points.length; i++) {
const p = this._originalToDisplayCoords(points[i].x, points[i].y);
const p = this._originalToViewportCoords(points[i].x, points[i].y);
this.offscreenUserCtx.lineTo(p.x, p.y);
}
this.offscreenUserCtx.strokeStyle = 'rgba(255,223,0,0.95)';
Expand Down
12 changes: 5 additions & 7 deletions app/frontend/static/js/main.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,6 @@ document.addEventListener("DOMContentLoaded", () => {
const uiManager = new UIManager();
const canvasManager = new CanvasManager();

const canvasStateCache = {};
let imageLayerCache = {};
let projectTagList = [];
let layerTagDebouncers = {};
Expand Down Expand Up @@ -367,13 +366,11 @@ document.addEventListener("DOMContentLoaded", () => {
}

function saveCanvasState(hash) {
if (!hash) return;
canvasStateCache[hash] = canvasManager.exportState();
// State caching of prediction inputs was removed
}

function restoreCanvasState(hash) {
const state = canvasStateCache[hash];
if (state) canvasManager.importState(state);
// Previously saved canvas state is ignored
}

function syncLayerCache(hash) {
Expand Down Expand Up @@ -611,8 +608,9 @@ document.addEventListener("DOMContentLoaded", () => {
const imageElement = new Image();
imageElement.onload = () => {
canvasManager.loadImageOntoCanvas(imageElement, width, height, filename);
const hadState = !!canvasStateCache[imageHash];
restoreCanvasState(imageHash);
canvasManager.setManualPredictions(null);
canvasManager.setAutomaskPredictions(null);
layerViewController && layerViewController.setSelectedLayers([]);
if (editModeController) editModeController.endEdit();
canvasManager.setMode("creation");
Expand Down Expand Up @@ -1125,7 +1123,7 @@ document.addEventListener("DOMContentLoaded", () => {
canvasManager.clearAllCanvasInputs(false);
canvasManager.setManualPredictions(null);
canvasManager.setAutomaskPredictions(null);
canvasManager.setMode("edit");
canvasManager.setMode("creation");
}

if (commitMasksBtn && !commitMasksBtn.dataset.listenerAttached) {
Expand Down