import {
ExcalidrawElement,
ExcalidrawLinearElement,
ExcalidrawTextElement,
Arrowhead,
NonDeletedExcalidrawElement,
ExcalidrawFreeDrawElement,
ExcalidrawImageElement,
ExcalidrawTextElementWithContainer,
} from "../element/types";
import {
isTextElement,
isLinearElement,
isFreeDrawElement,
isInitializedImageElement,
isArrowElement,
hasBoundTextElement,
} from "../element/typeChecks";
import {
getDiamondPoints,
getElementAbsoluteCoords,
getArrowheadPoints,
} from "../element/bounds";
import { RoughCanvas } from "roughjs/bin/canvas";
import { Drawable, Options } from "roughjs/bin/core";
import { RoughSVG } from "roughjs/bin/svg";
import { RoughGenerator } from "roughjs/bin/generator";
import { RenderConfig } from "../scene/types";
import {
distance,
getFontString,
getFontFamilyString,
isRTL,
isTransparent,
} from "../utils";
import { getCornerRadius, isPathALoop, isRightAngle } from "../math";
import rough from "roughjs/bin/rough";
import { AppState, BinaryFiles, Zoom } from "../types";
import { getDefaultAppState } from "../appState";
import {
BOUND_TEXT_PADDING,
FRAME_STYLE,
MAX_DECIMALS_FOR_SVG_EXPORT,
MIME_TYPES,
SVG_NS,
} from "../constants";
import { getStroke, StrokeOptions } from "perfect-freehand";
import {
getBoundTextElement,
getContainerCoords,
getContainerElement,
getLineHeightInPx,
getBoundTextMaxHeight,
getBoundTextMaxWidth,
} from "../element/textElement";
import { LinearElementEditor } from "../element/linearElementEditor";
import {
createPlaceholderEmbeddableLabel,
getEmbedLink,
} from "../element/embeddable";
import { getContainingFrame } from "../frame";
import { normalizeLink, toValidURL } from "../data/url";
// using a stronger invert (100% vs our regular 93%) and saturate
// as a temp hack to make images in dark theme look closer to original
// color scheme (it's still not quite there and the colors look slightly
// desatured, alas...)
const IMAGE_INVERT_FILTER = "invert(100%) hue-rotate(180deg) saturate(1.25)";
const defaultAppState = getDefaultAppState();
const isPendingImageElement = (
element: ExcalidrawElement,
renderConfig: RenderConfig,
) =>
isInitializedImageElement(element) &&
!renderConfig.imageCache.has(element.fileId);
const shouldResetImageFilter = (
element: ExcalidrawElement,
renderConfig: RenderConfig,
) => {
return (
renderConfig.theme === "dark" &&
isInitializedImageElement(element) &&
!isPendingImageElement(element, renderConfig) &&
renderConfig.imageCache.get(element.fileId)?.mimeType !== MIME_TYPES.svg
);
};
const getDashArrayDashed = (strokeWidth: number) => [8, 8 + strokeWidth];
const getDashArrayDotted = (strokeWidth: number) => [1.5, 6 + strokeWidth];
const getCanvasPadding = (element: ExcalidrawElement) =>
element.type === "freedraw" ? element.strokeWidth * 12 : 20;
export interface ExcalidrawElementWithCanvas {
element: ExcalidrawElement | ExcalidrawTextElement;
canvas: HTMLCanvasElement;
theme: RenderConfig["theme"];
scale: number;
zoomValue: RenderConfig["zoom"]["value"];
canvasOffsetX: number;
canvasOffsetY: number;
boundTextElementVersion: number | null;
containingFrameOpacity: number;
}
const cappedElementCanvasSize = (
element: NonDeletedExcalidrawElement,
zoom: Zoom,
): {
width: number;
height: number;
scale: number;
} => {
// these limits are ballpark, they depend on specific browsers and device.
// We've chosen lower limits to be safe. We might want to change these limits
// based on browser/device type, if we get reports of low quality rendering
// on zoom.
//
// ~ safari mobile canvas area limit
const AREA_LIMIT = 16777216;
// ~ safari width/height limit based on developer.mozilla.org.
const WIDTH_HEIGHT_LIMIT = 32767;
const padding = getCanvasPadding(element);
const [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
const elementWidth =
isLinearElement(element) || isFreeDrawElement(element)
? distance(x1, x2)
: element.width;
const elementHeight =
isLinearElement(element) || isFreeDrawElement(element)
? distance(y1, y2)
: element.height;
let width = elementWidth * window.devicePixelRatio + padding * 2;
let height = elementHeight * window.devicePixelRatio + padding * 2;
let scale: number = zoom.value;
// rescale to ensure width and height is within limits
if (
width * scale > WIDTH_HEIGHT_LIMIT ||
height * scale > WIDTH_HEIGHT_LIMIT
) {
scale = Math.min(WIDTH_HEIGHT_LIMIT / width, WIDTH_HEIGHT_LIMIT / height);
}
// rescale to ensure canvas area is within limits
if (width * height * scale * scale > AREA_LIMIT) {
scale = Math.sqrt(AREA_LIMIT / (width * height));
}
width = Math.floor(width * scale);
height = Math.floor(height * scale);
return { width, height, scale };
};
const generateElementCanvas = (
element: NonDeletedExcalidrawElement,
zoom: Zoom,
renderConfig: RenderConfig,
): ExcalidrawElementWithCanvas => {
const canvas = document.createElement("canvas");
const context = canvas.getContext("2d")!;
const padding = getCanvasPadding(element);
const { width, height, scale } = cappedElementCanvasSize(element, zoom);
canvas.width = width;
canvas.height = height;
let canvasOffsetX = 0;
let canvasOffsetY = 0;
if (isLinearElement(element) || isFreeDrawElement(element)) {
const [x1, y1] = getElementAbsoluteCoords(element);
canvasOffsetX =
element.x > x1
? distance(element.x, x1) * window.devicePixelRatio * scale
: 0;
canvasOffsetY =
element.y > y1
? distance(element.y, y1) * window.devicePixelRatio * scale
: 0;
context.translate(canvasOffsetX, canvasOffsetY);
}
context.save();
context.translate(padding * scale, padding * scale);
context.scale(
window.devicePixelRatio * scale,
window.devicePixelRatio * scale,
);
const rc = rough.canvas(canvas);
// in dark theme, revert the image color filter
if (shouldResetImageFilter(element, renderConfig)) {
context.filter = IMAGE_INVERT_FILTER;
}
drawElementOnCanvas(element, rc, context, renderConfig);
context.restore();
return {
element,
canvas,
theme: renderConfig.theme,
scale,
zoomValue: zoom.value,
canvasOffsetX,
canvasOffsetY,
boundTextElementVersion: getBoundTextElement(element)?.version || null,
containingFrameOpacity: getContainingFrame(element)?.opacity || 100,
};
};
export const DEFAULT_LINK_SIZE = 14;
const IMAGE_PLACEHOLDER_IMG = document.createElement("img");
IMAGE_PLACEHOLDER_IMG.src = `data:${MIME_TYPES.svg},${encodeURIComponent(
``,
)}`;
const IMAGE_ERROR_PLACEHOLDER_IMG = document.createElement("img");
IMAGE_ERROR_PLACEHOLDER_IMG.src = `data:${MIME_TYPES.svg},${encodeURIComponent(
``,
)}`;
const drawImagePlaceholder = (
element: ExcalidrawImageElement,
context: CanvasRenderingContext2D,
zoomValue: AppState["zoom"]["value"],
) => {
context.fillStyle = "#E7E7E7";
context.fillRect(0, 0, element.width, element.height);
const imageMinWidthOrHeight = Math.min(element.width, element.height);
const size = Math.min(
imageMinWidthOrHeight,
Math.min(imageMinWidthOrHeight * 0.4, 100),
);
context.drawImage(
element.status === "error"
? IMAGE_ERROR_PLACEHOLDER_IMG
: IMAGE_PLACEHOLDER_IMG,
element.width / 2 - size / 2,
element.height / 2 - size / 2,
size,
size,
);
};
const drawElementOnCanvas = (
element: NonDeletedExcalidrawElement,
rc: RoughCanvas,
context: CanvasRenderingContext2D,
renderConfig: RenderConfig,
) => {
context.globalAlpha =
((getContainingFrame(element)?.opacity ?? 100) * element.opacity) / 10000;
switch (element.type) {
case "rectangle":
case "embeddable":
case "diamond":
case "ellipse": {
context.lineJoin = "round";
context.lineCap = "round";
rc.draw(getShapeForElement(element)!);
break;
}
case "arrow":
case "line": {
context.lineJoin = "round";
context.lineCap = "round";
getShapeForElement(element)!.forEach((shape) => {
rc.draw(shape);
});
break;
}
case "freedraw": {
// Draw directly to canvas
context.save();
context.fillStyle = element.strokeColor;
const path = getFreeDrawPath2D(element) as Path2D;
const fillShape = getShapeForElement(element);
if (fillShape) {
rc.draw(fillShape);
}
context.fillStyle = element.strokeColor;
context.fill(path);
context.restore();
break;
}
case "image": {
const img = isInitializedImageElement(element)
? renderConfig.imageCache.get(element.fileId)?.image
: undefined;
if (img != null && !(img instanceof Promise)) {
context.drawImage(
img,
0 /* hardcoded for the selection box*/,
0,
element.width,
element.height,
);
} else {
drawImagePlaceholder(element, context, renderConfig.zoom.value);
}
break;
}
default: {
if (isTextElement(element)) {
const rtl = isRTL(element.text);
const shouldTemporarilyAttach = rtl && !context.canvas.isConnected;
if (shouldTemporarilyAttach) {
// to correctly render RTL text mixed with LTR, we have to append it
// to the DOM
document.body.appendChild(context.canvas);
}
context.canvas.setAttribute("dir", rtl ? "rtl" : "ltr");
context.save();
context.font = getFontString(element);
context.fillStyle = element.strokeColor;
context.textAlign = element.textAlign as CanvasTextAlign;
// Canvas does not support multiline text by default
const lines = element.text.replace(/\r\n?/g, "\n").split("\n");
const horizontalOffset =
element.textAlign === "center"
? element.width / 2
: element.textAlign === "right"
? element.width
: 0;
const lineHeightPx = getLineHeightInPx(
element.fontSize,
element.lineHeight,
);
const verticalOffset = element.height - element.baseline;
for (let index = 0; index < lines.length; index++) {
context.fillText(
lines[index],
horizontalOffset,
(index + 1) * lineHeightPx - verticalOffset,
);
}
context.restore();
if (shouldTemporarilyAttach) {
context.canvas.remove();
}
} else {
throw new Error(`Unimplemented type ${element.type}`);
}
}
}
context.globalAlpha = 1;
};
const elementWithCanvasCache = new WeakMap<
ExcalidrawElement,
ExcalidrawElementWithCanvas
>();
const shapeCache = new WeakMap();
type ElementShape = Drawable | Drawable[] | null;
type ElementShapes = {
freedraw: Drawable | null;
arrow: Drawable[];
line: Drawable[];
text: null;
image: null;
};
export const getShapeForElement = (element: T) =>
shapeCache.get(element) as T["type"] extends keyof ElementShapes
? ElementShapes[T["type"]] | undefined
: Drawable | null | undefined;
export const setShapeForElement = (
element: T,
shape: T["type"] extends keyof ElementShapes
? ElementShapes[T["type"]]
: Drawable,
) => shapeCache.set(element, shape);
export const invalidateShapeForElement = (element: ExcalidrawElement) =>
shapeCache.delete(element);
export const generateRoughOptions = (
element: ExcalidrawElement,
continuousPath = false,
): Options => {
const options: Options = {
seed: element.seed,
strokeLineDash:
element.strokeStyle === "dashed"
? getDashArrayDashed(element.strokeWidth)
: element.strokeStyle === "dotted"
? getDashArrayDotted(element.strokeWidth)
: undefined,
// for non-solid strokes, disable multiStroke because it tends to make
// dashes/dots overlay each other
disableMultiStroke: element.strokeStyle !== "solid",
// for non-solid strokes, increase the width a bit to make it visually
// similar to solid strokes, because we're also disabling multiStroke
strokeWidth:
element.strokeStyle !== "solid"
? element.strokeWidth + 0.5
: element.strokeWidth,
// when increasing strokeWidth, we must explicitly set fillWeight and
// hachureGap because if not specified, roughjs uses strokeWidth to
// calculate them (and we don't want the fills to be modified)
fillWeight: element.strokeWidth / 2,
hachureGap: element.strokeWidth * 4,
roughness: element.roughness,
stroke: element.strokeColor,
preserveVertices: continuousPath,
};
switch (element.type) {
case "rectangle":
case "embeddable":
case "diamond":
case "ellipse": {
options.fillStyle = element.fillStyle;
options.fill = isTransparent(element.backgroundColor)
? undefined
: element.backgroundColor;
if (element.type === "ellipse") {
options.curveFitting = 1;
}
return options;
}
case "line":
case "freedraw": {
if (isPathALoop(element.points)) {
options.fillStyle = element.fillStyle;
options.fill =
element.backgroundColor === "transparent"
? undefined
: element.backgroundColor;
}
return options;
}
case "arrow":
return options;
default: {
throw new Error(`Unimplemented type ${element.type}`);
}
}
};
const modifyEmbeddableForRoughOptions = (
element: NonDeletedExcalidrawElement,
isExporting: boolean,
) => {
if (
element.type === "embeddable" &&
(isExporting || !element.validated) &&
isTransparent(element.backgroundColor) &&
isTransparent(element.strokeColor)
) {
return {
...element,
roughness: 0,
backgroundColor: "#d3d3d3",
fillStyle: "solid",
} as const;
}
return element;
};
/**
* Generates the element's shape and puts it into the cache.
* @param element
* @param generator
*/
const generateElementShape = (
element: NonDeletedExcalidrawElement,
generator: RoughGenerator,
isExporting: boolean = false,
) => {
let shape = isExporting ? undefined : shapeCache.get(element);
// `null` indicates no rc shape applicable for this element type
// (= do not generate anything)
if (shape === undefined) {
elementWithCanvasCache.delete(element);
switch (element.type) {
case "rectangle":
case "embeddable": {
// this is for rendering the stroke/bg of the embeddable, especially
// when the src url is not set
if (element.roundness) {
const w = element.width;
const h = element.height;
const r = getCornerRadius(Math.min(w, h), element);
shape = generator.path(
`M ${r} 0 L ${w - r} 0 Q ${w} 0, ${w} ${r} L ${w} ${
h - r
} Q ${w} ${h}, ${w - r} ${h} L ${r} ${h} Q 0 ${h}, 0 ${
h - r
} L 0 ${r} Q 0 0, ${r} 0`,
generateRoughOptions(
modifyEmbeddableForRoughOptions(element, isExporting),
true,
),
);
} else {
shape = generator.rectangle(
0,
0,
element.width,
element.height,
generateRoughOptions(
modifyEmbeddableForRoughOptions(element, isExporting),
false,
),
);
}
setShapeForElement(element, shape);
break;
}
case "diamond": {
const [topX, topY, rightX, rightY, bottomX, bottomY, leftX, leftY] =
getDiamondPoints(element);
if (element.roundness) {
const verticalRadius = getCornerRadius(
Math.abs(topX - leftX),
element,
);
const horizontalRadius = getCornerRadius(
Math.abs(rightY - topY),
element,
);
shape = generator.path(
`M ${topX + verticalRadius} ${topY + horizontalRadius} L ${
rightX - verticalRadius
} ${rightY - horizontalRadius}
C ${rightX} ${rightY}, ${rightX} ${rightY}, ${
rightX - verticalRadius
} ${rightY + horizontalRadius}
L ${bottomX + verticalRadius} ${bottomY - horizontalRadius}
C ${bottomX} ${bottomY}, ${bottomX} ${bottomY}, ${
bottomX - verticalRadius
} ${bottomY - horizontalRadius}
L ${leftX + verticalRadius} ${leftY + horizontalRadius}
C ${leftX} ${leftY}, ${leftX} ${leftY}, ${leftX + verticalRadius} ${
leftY - horizontalRadius
}
L ${topX - verticalRadius} ${topY + horizontalRadius}
C ${topX} ${topY}, ${topX} ${topY}, ${topX + verticalRadius} ${
topY + horizontalRadius
}`,
generateRoughOptions(element, true),
);
} else {
shape = generator.polygon(
[
[topX, topY],
[rightX, rightY],
[bottomX, bottomY],
[leftX, leftY],
],
generateRoughOptions(element),
);
}
setShapeForElement(element, shape);
break;
}
case "ellipse":
shape = generator.ellipse(
element.width / 2,
element.height / 2,
element.width,
element.height,
generateRoughOptions(element),
);
setShapeForElement(element, shape);
break;
case "line":
case "arrow": {
const options = generateRoughOptions(element);
// points array can be empty in the beginning, so it is important to add
// initial position to it
const points = element.points.length ? element.points : [[0, 0]];
// curve is always the first element
// this simplifies finding the curve for an element
if (!element.roundness) {
if (options.fill) {
shape = [generator.polygon(points as [number, number][], options)];
} else {
shape = [
generator.linearPath(points as [number, number][], options),
];
}
} else {
shape = [generator.curve(points as [number, number][], options)];
}
// add lines only in arrow
if (element.type === "arrow") {
const { startArrowhead = null, endArrowhead = "arrow" } = element;
const getArrowheadShapes = (
element: ExcalidrawLinearElement,
shape: Drawable[],
position: "start" | "end",
arrowhead: Arrowhead,
) => {
const arrowheadPoints = getArrowheadPoints(
element,
shape,
position,
arrowhead,
);
if (arrowheadPoints === null) {
return [];
}
// Other arrowheads here...
if (arrowhead === "dot") {
const [x, y, r] = arrowheadPoints;
return [
generator.circle(x, y, r, {
...options,
fill: element.strokeColor,
fillStyle: "solid",
stroke: "none",
}),
];
}
if (arrowhead === "triangle") {
const [x, y, x2, y2, x3, y3] = arrowheadPoints;
// always use solid stroke for triangle arrowhead
delete options.strokeLineDash;
return [
generator.polygon(
[
[x, y],
[x2, y2],
[x3, y3],
[x, y],
],
{
...options,
fill: element.strokeColor,
fillStyle: "solid",
},
),
];
}
// Arrow arrowheads
const [x2, y2, x3, y3, x4, y4] = arrowheadPoints;
if (element.strokeStyle === "dotted") {
// for dotted arrows caps, reduce gap to make it more legible
const dash = getDashArrayDotted(element.strokeWidth - 1);
options.strokeLineDash = [dash[0], dash[1] - 1];
} else {
// for solid/dashed, keep solid arrow cap
delete options.strokeLineDash;
}
return [
generator.line(x3, y3, x2, y2, options),
generator.line(x4, y4, x2, y2, options),
];
};
if (startArrowhead !== null) {
const shapes = getArrowheadShapes(
element,
shape,
"start",
startArrowhead,
);
shape.push(...shapes);
}
if (endArrowhead !== null) {
if (endArrowhead === undefined) {
// Hey, we have an old arrow here!
}
const shapes = getArrowheadShapes(
element,
shape,
"end",
endArrowhead,
);
shape.push(...shapes);
}
}
setShapeForElement(element, shape);
break;
}
case "freedraw": {
generateFreeDrawShape(element);
if (isPathALoop(element.points)) {
// generate rough polygon to fill freedraw shape
shape = generator.polygon(element.points as [number, number][], {
...generateRoughOptions(element),
stroke: "none",
});
} else {
shape = null;
}
setShapeForElement(element, shape);
break;
}
case "text":
case "image": {
// just to ensure we don't regenerate element.canvas on rerenders
setShapeForElement(element, null);
break;
}
}
}
};
const generateElementWithCanvas = (
element: NonDeletedExcalidrawElement,
renderConfig: RenderConfig,
) => {
const zoom: Zoom = renderConfig ? renderConfig.zoom : defaultAppState.zoom;
const prevElementWithCanvas = elementWithCanvasCache.get(element);
const shouldRegenerateBecauseZoom =
prevElementWithCanvas &&
prevElementWithCanvas.zoomValue !== zoom.value &&
!renderConfig?.shouldCacheIgnoreZoom;
const boundTextElementVersion = getBoundTextElement(element)?.version || null;
const containingFrameOpacity = getContainingFrame(element)?.opacity || 100;
if (
!prevElementWithCanvas ||
shouldRegenerateBecauseZoom ||
prevElementWithCanvas.theme !== renderConfig.theme ||
prevElementWithCanvas.boundTextElementVersion !== boundTextElementVersion ||
prevElementWithCanvas.containingFrameOpacity !== containingFrameOpacity
) {
const elementWithCanvas = generateElementCanvas(
element,
zoom,
renderConfig,
);
elementWithCanvasCache.set(element, elementWithCanvas);
return elementWithCanvas;
}
return prevElementWithCanvas;
};
const drawElementFromCanvas = (
elementWithCanvas: ExcalidrawElementWithCanvas,
rc: RoughCanvas,
context: CanvasRenderingContext2D,
renderConfig: RenderConfig,
) => {
const element = elementWithCanvas.element;
const padding = getCanvasPadding(element);
const zoom = elementWithCanvas.scale;
let [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
// Free draw elements will otherwise "shuffle" as the min x and y change
if (isFreeDrawElement(element)) {
x1 = Math.floor(x1);
x2 = Math.ceil(x2);
y1 = Math.floor(y1);
y2 = Math.ceil(y2);
}
const cx = ((x1 + x2) / 2 + renderConfig.scrollX) * window.devicePixelRatio;
const cy = ((y1 + y2) / 2 + renderConfig.scrollY) * window.devicePixelRatio;
context.save();
context.scale(1 / window.devicePixelRatio, 1 / window.devicePixelRatio);
const boundTextElement = getBoundTextElement(element);
if (isArrowElement(element) && boundTextElement) {
const tempCanvas = document.createElement("canvas");
const tempCanvasContext = tempCanvas.getContext("2d")!;
// Take max dimensions of arrow canvas so that when canvas is rotated
// the arrow doesn't get clipped
const maxDim = Math.max(distance(x1, x2), distance(y1, y2));
tempCanvas.width =
maxDim * window.devicePixelRatio * zoom +
padding * elementWithCanvas.scale * 10;
tempCanvas.height =
maxDim * window.devicePixelRatio * zoom +
padding * elementWithCanvas.scale * 10;
const offsetX = (tempCanvas.width - elementWithCanvas.canvas!.width) / 2;
const offsetY = (tempCanvas.height - elementWithCanvas.canvas!.height) / 2;
tempCanvasContext.translate(tempCanvas.width / 2, tempCanvas.height / 2);
tempCanvasContext.rotate(element.angle);
tempCanvasContext.drawImage(
elementWithCanvas.canvas!,
-elementWithCanvas.canvas.width / 2,
-elementWithCanvas.canvas.height / 2,
elementWithCanvas.canvas.width,
elementWithCanvas.canvas.height,
);
const [, , , , boundTextCx, boundTextCy] =
getElementAbsoluteCoords(boundTextElement);
tempCanvasContext.rotate(-element.angle);
// Shift the canvas to the center of the bound text element
const shiftX =
tempCanvas.width / 2 -
(boundTextCx - x1) * window.devicePixelRatio * zoom -
offsetX -
padding * zoom;
const shiftY =
tempCanvas.height / 2 -
(boundTextCy - y1) * window.devicePixelRatio * zoom -
offsetY -
padding * zoom;
tempCanvasContext.translate(-shiftX, -shiftY);
// Clear the bound text area
tempCanvasContext.clearRect(
-(boundTextElement.width / 2 + BOUND_TEXT_PADDING) *
window.devicePixelRatio *
zoom,
-(boundTextElement.height / 2 + BOUND_TEXT_PADDING) *
window.devicePixelRatio *
zoom,
(boundTextElement.width + BOUND_TEXT_PADDING * 2) *
window.devicePixelRatio *
zoom,
(boundTextElement.height + BOUND_TEXT_PADDING * 2) *
window.devicePixelRatio *
zoom,
);
context.translate(cx, cy);
context.drawImage(
tempCanvas,
(-(x2 - x1) / 2) * window.devicePixelRatio - offsetX / zoom - padding,
(-(y2 - y1) / 2) * window.devicePixelRatio - offsetY / zoom - padding,
tempCanvas.width / zoom,
tempCanvas.height / zoom,
);
} else {
// we translate context to element center so that rotation and scale
// originates from the element center
context.translate(cx, cy);
context.rotate(element.angle);
if (
"scale" in elementWithCanvas.element &&
!isPendingImageElement(element, renderConfig)
) {
context.scale(
elementWithCanvas.element.scale[0],
elementWithCanvas.element.scale[1],
);
}
// revert afterwards we don't have account for it during drawing
context.translate(-cx, -cy);
context.drawImage(
elementWithCanvas.canvas!,
(x1 + renderConfig.scrollX) * window.devicePixelRatio -
(padding * elementWithCanvas.scale) / elementWithCanvas.scale,
(y1 + renderConfig.scrollY) * window.devicePixelRatio -
(padding * elementWithCanvas.scale) / elementWithCanvas.scale,
elementWithCanvas.canvas!.width / elementWithCanvas.scale,
elementWithCanvas.canvas!.height / elementWithCanvas.scale,
);
if (
import.meta.env.VITE_APP_DEBUG_ENABLE_TEXT_CONTAINER_BOUNDING_BOX ===
"true" &&
hasBoundTextElement(element)
) {
const textElement = getBoundTextElement(
element,
) as ExcalidrawTextElementWithContainer;
const coords = getContainerCoords(element);
context.strokeStyle = "#c92a2a";
context.lineWidth = 3;
context.strokeRect(
(coords.x + renderConfig.scrollX) * window.devicePixelRatio,
(coords.y + renderConfig.scrollY) * window.devicePixelRatio,
getBoundTextMaxWidth(element) * window.devicePixelRatio,
getBoundTextMaxHeight(element, textElement) * window.devicePixelRatio,
);
}
}
context.restore();
// Clear the nested element we appended to the DOM
};
export const renderElement = (
element: NonDeletedExcalidrawElement,
rc: RoughCanvas,
context: CanvasRenderingContext2D,
renderConfig: RenderConfig,
appState: AppState,
) => {
const generator = rc.generator;
switch (element.type) {
case "selection": {
// do not render selection when exporting
if (!renderConfig.isExporting) {
context.save();
context.translate(
element.x + renderConfig.scrollX,
element.y + renderConfig.scrollY,
);
context.fillStyle = "rgba(0, 0, 200, 0.04)";
// render from 0.5px offset to get 1px wide line
// https://stackoverflow.com/questions/7530593/html5-canvas-and-line-width/7531540#7531540
// TODO can be be improved by offseting to the negative when user selects
// from right to left
const offset = 0.5 / renderConfig.zoom.value;
context.fillRect(offset, offset, element.width, element.height);
context.lineWidth = 1 / renderConfig.zoom.value;
context.strokeStyle = " rgb(105, 101, 219)";
context.strokeRect(offset, offset, element.width, element.height);
context.restore();
}
break;
}
case "frame": {
if (
!renderConfig.isExporting &&
appState.frameRendering.enabled &&
appState.frameRendering.outline
) {
context.save();
context.translate(
element.x + renderConfig.scrollX,
element.y + renderConfig.scrollY,
);
context.fillStyle = "rgba(0, 0, 200, 0.04)";
context.lineWidth = 2 / renderConfig.zoom.value;
context.strokeStyle = FRAME_STYLE.strokeColor;
if (FRAME_STYLE.radius && context.roundRect) {
context.beginPath();
context.roundRect(
0,
0,
element.width,
element.height,
FRAME_STYLE.radius / renderConfig.zoom.value,
);
context.stroke();
context.closePath();
} else {
context.strokeRect(0, 0, element.width, element.height);
}
context.restore();
}
break;
}
case "freedraw": {
generateElementShape(element, generator);
if (renderConfig.isExporting) {
const [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
const cx = (x1 + x2) / 2 + renderConfig.scrollX;
const cy = (y1 + y2) / 2 + renderConfig.scrollY;
const shiftX = (x2 - x1) / 2 - (element.x - x1);
const shiftY = (y2 - y1) / 2 - (element.y - y1);
context.save();
context.translate(cx, cy);
context.rotate(element.angle);
context.translate(-shiftX, -shiftY);
drawElementOnCanvas(element, rc, context, renderConfig);
context.restore();
} else {
const elementWithCanvas = generateElementWithCanvas(
element,
renderConfig,
);
drawElementFromCanvas(elementWithCanvas, rc, context, renderConfig);
}
break;
}
case "rectangle":
case "diamond":
case "ellipse":
case "line":
case "arrow":
case "image":
case "text":
case "embeddable": {
generateElementShape(element, generator, renderConfig.isExporting);
if (renderConfig.isExporting) {
const [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
const cx = (x1 + x2) / 2 + renderConfig.scrollX;
const cy = (y1 + y2) / 2 + renderConfig.scrollY;
let shiftX = (x2 - x1) / 2 - (element.x - x1);
let shiftY = (y2 - y1) / 2 - (element.y - y1);
if (isTextElement(element)) {
const container = getContainerElement(element);
if (isArrowElement(container)) {
const boundTextCoords =
LinearElementEditor.getBoundTextElementPosition(
container,
element as ExcalidrawTextElementWithContainer,
);
shiftX = (x2 - x1) / 2 - (boundTextCoords.x - x1);
shiftY = (y2 - y1) / 2 - (boundTextCoords.y - y1);
}
}
context.save();
context.translate(cx, cy);
if (shouldResetImageFilter(element, renderConfig)) {
context.filter = "none";
}
const boundTextElement = getBoundTextElement(element);
if (isArrowElement(element) && boundTextElement) {
const tempCanvas = document.createElement("canvas");
const tempCanvasContext = tempCanvas.getContext("2d")!;
// Take max dimensions of arrow canvas so that when canvas is rotated
// the arrow doesn't get clipped
const maxDim = Math.max(distance(x1, x2), distance(y1, y2));
const padding = getCanvasPadding(element);
tempCanvas.width =
maxDim * appState.exportScale + padding * 10 * appState.exportScale;
tempCanvas.height =
maxDim * appState.exportScale + padding * 10 * appState.exportScale;
tempCanvasContext.translate(
tempCanvas.width / 2,
tempCanvas.height / 2,
);
tempCanvasContext.scale(appState.exportScale, appState.exportScale);
// Shift the canvas to left most point of the arrow
shiftX = element.width / 2 - (element.x - x1);
shiftY = element.height / 2 - (element.y - y1);
tempCanvasContext.rotate(element.angle);
const tempRc = rough.canvas(tempCanvas);
tempCanvasContext.translate(-shiftX, -shiftY);
drawElementOnCanvas(element, tempRc, tempCanvasContext, renderConfig);
tempCanvasContext.translate(shiftX, shiftY);
tempCanvasContext.rotate(-element.angle);
// Shift the canvas to center of bound text
const [, , , , boundTextCx, boundTextCy] =
getElementAbsoluteCoords(boundTextElement);
const boundTextShiftX = (x1 + x2) / 2 - boundTextCx;
const boundTextShiftY = (y1 + y2) / 2 - boundTextCy;
tempCanvasContext.translate(-boundTextShiftX, -boundTextShiftY);
// Clear the bound text area
tempCanvasContext.clearRect(
-boundTextElement.width / 2,
-boundTextElement.height / 2,
boundTextElement.width,
boundTextElement.height,
);
context.scale(1 / appState.exportScale, 1 / appState.exportScale);
context.drawImage(
tempCanvas,
-tempCanvas.width / 2,
-tempCanvas.height / 2,
tempCanvas.width,
tempCanvas.height,
);
} else {
context.rotate(element.angle);
if (element.type === "image") {
// note: scale must be applied *after* rotating
context.scale(element.scale[0], element.scale[1]);
}
context.translate(-shiftX, -shiftY);
drawElementOnCanvas(element, rc, context, renderConfig);
}
context.restore();
// not exporting → optimized rendering (cache & render from element
// canvases)
} else {
const elementWithCanvas = generateElementWithCanvas(
element,
renderConfig,
);
const currentImageSmoothingStatus = context.imageSmoothingEnabled;
if (
// do not disable smoothing during zoom as blurry shapes look better
// on low resolution (while still zooming in) than sharp ones
!renderConfig?.shouldCacheIgnoreZoom &&
// angle is 0 -> always disable smoothing
(!element.angle ||
// or check if angle is a right angle in which case we can still
// disable smoothing without adversely affecting the result
isRightAngle(element.angle))
) {
// Disabling smoothing makes output much sharper, especially for
// text. Unless for non-right angles, where the aliasing is really
// terrible on Chromium.
//
// Note that `context.imageSmoothingQuality="high"` has almost
// zero effect.
//
context.imageSmoothingEnabled = false;
}
drawElementFromCanvas(elementWithCanvas, rc, context, renderConfig);
// reset
context.imageSmoothingEnabled = currentImageSmoothingStatus;
}
break;
}
default: {
// @ts-ignore
throw new Error(`Unimplemented type ${element.type}`);
}
}
};
const roughSVGDrawWithPrecision = (
rsvg: RoughSVG,
drawable: Drawable,
precision?: number,
) => {
if (typeof precision === "undefined") {
return rsvg.draw(drawable);
}
const pshape: Drawable = {
sets: drawable.sets,
shape: drawable.shape,
options: { ...drawable.options, fixedDecimalPlaceDigits: precision },
};
return rsvg.draw(pshape);
};
const maybeWrapNodesInFrameClipPath = (
element: NonDeletedExcalidrawElement,
root: SVGElement,
nodes: SVGElement[],
exportedFrameId?: string | null,
) => {
const frame = getContainingFrame(element);
if (frame && frame.id === exportedFrameId) {
const g = root.ownerDocument!.createElementNS(SVG_NS, "g");
g.setAttributeNS(SVG_NS, "clip-path", `url(#${frame.id})`);
nodes.forEach((node) => g.appendChild(node));
return g;
}
return null;
};
export const renderElementToSvg = (
element: NonDeletedExcalidrawElement,
rsvg: RoughSVG,
svgRoot: SVGElement,
files: BinaryFiles,
offsetX: number,
offsetY: number,
exportWithDarkMode?: boolean,
exportingFrameId?: string | null,
renderEmbeddables?: boolean,
) => {
const offset = { x: offsetX, y: offsetY };
const [x1, y1, x2, y2] = getElementAbsoluteCoords(element);
let cx = (x2 - x1) / 2 - (element.x - x1);
let cy = (y2 - y1) / 2 - (element.y - y1);
if (isTextElement(element)) {
const container = getContainerElement(element);
if (isArrowElement(container)) {
const [x1, y1, x2, y2] = getElementAbsoluteCoords(container);
const boundTextCoords = LinearElementEditor.getBoundTextElementPosition(
container,
element as ExcalidrawTextElementWithContainer,
);
cx = (x2 - x1) / 2 - (boundTextCoords.x - x1);
cy = (y2 - y1) / 2 - (boundTextCoords.y - y1);
offsetX = offsetX + boundTextCoords.x - element.x;
offsetY = offsetY + boundTextCoords.y - element.y;
}
}
const degree = (180 * element.angle) / Math.PI;
const generator = rsvg.generator;
// element to append node to, most of the time svgRoot
let root = svgRoot;
// if the element has a link, create an anchor tag and make that the new root
if (element.link) {
const anchorTag = svgRoot.ownerDocument!.createElementNS(SVG_NS, "a");
anchorTag.setAttribute("href", normalizeLink(element.link));
root.appendChild(anchorTag);
root = anchorTag;
}
const opacity =
((getContainingFrame(element)?.opacity ?? 100) * element.opacity) / 10000;
switch (element.type) {
case "selection": {
// Since this is used only during editing experience, which is canvas based,
// this should not happen
throw new Error("Selection rendering is not supported for SVG");
}
case "rectangle":
case "diamond":
case "ellipse": {
generateElementShape(element, generator);
const node = roughSVGDrawWithPrecision(
rsvg,
getShapeForElement(element)!,
MAX_DECIMALS_FOR_SVG_EXPORT,
);
if (opacity !== 1) {
node.setAttribute("stroke-opacity", `${opacity}`);
node.setAttribute("fill-opacity", `${opacity}`);
}
node.setAttribute("stroke-linecap", "round");
node.setAttribute(
"transform",
`translate(${offsetX || 0} ${
offsetY || 0
}) rotate(${degree} ${cx} ${cy})`,
);
const g = maybeWrapNodesInFrameClipPath(
element,
root,
[node],
exportingFrameId,
);
g ? root.appendChild(g) : root.appendChild(node);
break;
}
case "embeddable": {
// render placeholder rectangle
generateElementShape(element, generator, true);
const node = roughSVGDrawWithPrecision(
rsvg,
getShapeForElement(element)!,
MAX_DECIMALS_FOR_SVG_EXPORT,
);
const opacity = element.opacity / 100;
if (opacity !== 1) {
node.setAttribute("stroke-opacity", `${opacity}`);
node.setAttribute("fill-opacity", `${opacity}`);
}
node.setAttribute("stroke-linecap", "round");
node.setAttribute(
"transform",
`translate(${offsetX || 0} ${
offsetY || 0
}) rotate(${degree} ${cx} ${cy})`,
);
root.appendChild(node);
const label: ExcalidrawElement =
createPlaceholderEmbeddableLabel(element);
renderElementToSvg(
label,
rsvg,
root,
files,
label.x + offset.x - element.x,
label.y + offset.y - element.y,
exportWithDarkMode,
exportingFrameId,
renderEmbeddables,
);
// render embeddable element + iframe
const embeddableNode = roughSVGDrawWithPrecision(
rsvg,
getShapeForElement(element)!,
MAX_DECIMALS_FOR_SVG_EXPORT,
);
embeddableNode.setAttribute("stroke-linecap", "round");
embeddableNode.setAttribute(
"transform",
`translate(${offsetX || 0} ${
offsetY || 0
}) rotate(${degree} ${cx} ${cy})`,
);
while (embeddableNode.firstChild) {
embeddableNode.removeChild(embeddableNode.firstChild);
}
const radius = getCornerRadius(
Math.min(element.width, element.height),
element,
);
const embedLink = getEmbedLink(toValidURL(element.link || ""));
// if rendering embeddables explicitly disabled or
// embedding documents via srcdoc (which doesn't seem to work for SVGs)
// replace with a link instead
if (renderEmbeddables === false || embedLink?.type === "document") {
const anchorTag = svgRoot.ownerDocument!.createElementNS(SVG_NS, "a");
anchorTag.setAttribute("href", normalizeLink(element.link || ""));
anchorTag.setAttribute("target", "_blank");
anchorTag.setAttribute("rel", "noopener noreferrer");
anchorTag.style.borderRadius = `${radius}px`;
embeddableNode.appendChild(anchorTag);
} else {
const foreignObject = svgRoot.ownerDocument!.createElementNS(
SVG_NS,
"foreignObject",
);
foreignObject.style.width = `${element.width}px`;
foreignObject.style.height = `${element.height}px`;
foreignObject.style.border = "none";
const div = foreignObject.ownerDocument!.createElementNS(SVG_NS, "div");
div.setAttribute("xmlns", "http://www.w3.org/1999/xhtml");
div.style.width = "100%";
div.style.height = "100%";
const iframe = div.ownerDocument!.createElement("iframe");
iframe.src = embedLink?.link ?? "";
iframe.style.width = "100%";
iframe.style.height = "100%";
iframe.style.border = "none";
iframe.style.borderRadius = `${radius}px`;
iframe.style.top = "0";
iframe.style.left = "0";
iframe.allowFullscreen = true;
div.appendChild(iframe);
foreignObject.appendChild(div);
embeddableNode.appendChild(foreignObject);
}
root.appendChild(embeddableNode);
break;
}
case "line":
case "arrow": {
const boundText = getBoundTextElement(element);
const maskPath = svgRoot.ownerDocument!.createElementNS(SVG_NS, "mask");
if (boundText) {
maskPath.setAttribute("id", `mask-${element.id}`);
const maskRectVisible = svgRoot.ownerDocument!.createElementNS(
SVG_NS,
"rect",
);
offsetX = offsetX || 0;
offsetY = offsetY || 0;
maskRectVisible.setAttribute("x", "0");
maskRectVisible.setAttribute("y", "0");
maskRectVisible.setAttribute("fill", "#fff");
maskRectVisible.setAttribute(
"width",
`${element.width + 100 + offsetX}`,
);
maskRectVisible.setAttribute(
"height",
`${element.height + 100 + offsetY}`,
);
maskPath.appendChild(maskRectVisible);
const maskRectInvisible = svgRoot.ownerDocument!.createElementNS(
SVG_NS,
"rect",
);
const boundTextCoords = LinearElementEditor.getBoundTextElementPosition(
element,
boundText,
);
const maskX = offsetX + boundTextCoords.x - element.x;
const maskY = offsetY + boundTextCoords.y - element.y;
maskRectInvisible.setAttribute("x", maskX.toString());
maskRectInvisible.setAttribute("y", maskY.toString());
maskRectInvisible.setAttribute("fill", "#000");
maskRectInvisible.setAttribute("width", `${boundText.width}`);
maskRectInvisible.setAttribute("height", `${boundText.height}`);
maskRectInvisible.setAttribute("opacity", "1");
maskPath.appendChild(maskRectInvisible);
}
generateElementShape(element, generator);
const group = svgRoot.ownerDocument!.createElementNS(SVG_NS, "g");
if (boundText) {
group.setAttribute("mask", `url(#mask-${element.id})`);
}
group.setAttribute("stroke-linecap", "round");
getShapeForElement(element)!.forEach((shape) => {
const node = roughSVGDrawWithPrecision(
rsvg,
shape,
MAX_DECIMALS_FOR_SVG_EXPORT,
);
if (opacity !== 1) {
node.setAttribute("stroke-opacity", `${opacity}`);
node.setAttribute("fill-opacity", `${opacity}`);
}
node.setAttribute(
"transform",
`translate(${offsetX || 0} ${
offsetY || 0
}) rotate(${degree} ${cx} ${cy})`,
);
if (
element.type === "line" &&
isPathALoop(element.points) &&
element.backgroundColor !== "transparent"
) {
node.setAttribute("fill-rule", "evenodd");
}
group.appendChild(node);
});
const g = maybeWrapNodesInFrameClipPath(
element,
root,
[group, maskPath],
exportingFrameId,
);
if (g) {
root.appendChild(g);
} else {
root.appendChild(group);
root.append(maskPath);
}
break;
}
case "freedraw": {
generateElementShape(element, generator);
generateFreeDrawShape(element);
const shape = getShapeForElement(element);
const node = shape
? roughSVGDrawWithPrecision(rsvg, shape, MAX_DECIMALS_FOR_SVG_EXPORT)
: svgRoot.ownerDocument!.createElementNS(SVG_NS, "g");
if (opacity !== 1) {
node.setAttribute("stroke-opacity", `${opacity}`);
node.setAttribute("fill-opacity", `${opacity}`);
}
node.setAttribute(
"transform",
`translate(${offsetX || 0} ${
offsetY || 0
}) rotate(${degree} ${cx} ${cy})`,
);
node.setAttribute("stroke", "none");
const path = svgRoot.ownerDocument!.createElementNS(SVG_NS, "path");
path.setAttribute("fill", element.strokeColor);
path.setAttribute("d", getFreeDrawSvgPath(element));
node.appendChild(path);
const g = maybeWrapNodesInFrameClipPath(
element,
root,
[node],
exportingFrameId,
);
g ? root.appendChild(g) : root.appendChild(node);
break;
}
case "image": {
const width = Math.round(element.width);
const height = Math.round(element.height);
const fileData =
isInitializedImageElement(element) && files[element.fileId];
if (fileData) {
const symbolId = `image-${fileData.id}`;
let symbol = svgRoot.querySelector(`#${symbolId}`);
if (!symbol) {
symbol = svgRoot.ownerDocument!.createElementNS(SVG_NS, "symbol");
symbol.id = symbolId;
const image = svgRoot.ownerDocument!.createElementNS(SVG_NS, "image");
image.setAttribute("width", "100%");
image.setAttribute("height", "100%");
image.setAttribute("href", fileData.dataURL);
symbol.appendChild(image);
root.prepend(symbol);
}
const use = svgRoot.ownerDocument!.createElementNS(SVG_NS, "use");
use.setAttribute("href", `#${symbolId}`);
// in dark theme, revert the image color filter
if (exportWithDarkMode && fileData.mimeType !== MIME_TYPES.svg) {
use.setAttribute("filter", IMAGE_INVERT_FILTER);
}
use.setAttribute("width", `${width}`);
use.setAttribute("height", `${height}`);
use.setAttribute("opacity", `${opacity}`);
// We first apply `scale` transforms (horizontal/vertical mirroring)
// on the