Files
excalidraw/packages/element/src/shape.ts

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27 KiB
TypeScript

import { simplify } from "points-on-curve";
import {
type GeometricShape,
getClosedCurveShape,
getCurveShape,
getEllipseShape,
getFreedrawShape,
getPolygonShape,
} from "@excalidraw/utils/shape";
import {
pointFrom,
pointDistance,
type LocalPoint,
pointRotateRads,
} from "@excalidraw/math";
import {
ROUGHNESS,
isTransparent,
assertNever,
COLOR_PALETTE,
LINE_POLYGON_POINT_MERGE_DISTANCE,
} from "@excalidraw/common";
import { RoughGenerator } from "roughjs/bin/generator";
import type { GlobalPoint } from "@excalidraw/math";
import type { Mutable } from "@excalidraw/common/utility-types";
import type {
AppState,
EmbedsValidationStatus,
} from "@excalidraw/excalidraw/types";
import type {
ElementShape,
ElementShapes,
} from "@excalidraw/excalidraw/scene/types";
import { elementWithCanvasCache } from "./renderElement";
import {
canBecomePolygon,
isElbowArrow,
isEmbeddableElement,
isIframeElement,
isIframeLikeElement,
isLinearElement,
} from "./typeChecks";
import { getCornerRadius, isPathALoop } from "./utils";
import { headingForPointIsHorizontal } from "./heading";
import { canChangeRoundness } from "./comparisons";
import { generateFreeDrawShape } from "./renderElement";
import {
getArrowheadPoints,
getCenterForBounds,
getDiamondPoints,
getElementAbsoluteCoords,
} from "./bounds";
import { shouldTestInside } from "./collision";
import type {
ExcalidrawElement,
NonDeletedExcalidrawElement,
ExcalidrawSelectionElement,
ExcalidrawLinearElement,
Arrowhead,
ExcalidrawFreeDrawElement,
ElementsMap,
ExcalidrawLineElement,
} from "./types";
import type { Drawable, Options } from "roughjs/bin/core";
import type { Point as RoughPoint } from "roughjs/bin/geometry";
export class ShapeCache {
private static rg = new RoughGenerator();
private static cache = new WeakMap<ExcalidrawElement, ElementShape>();
/**
* Retrieves shape from cache if available. Use this only if shape
* is optional and you have a fallback in case it's not cached.
*/
public static get = <T extends ExcalidrawElement>(element: T) => {
return ShapeCache.cache.get(
element,
) as T["type"] extends keyof ElementShapes
? ElementShapes[T["type"]] | undefined
: ElementShape | undefined;
};
public static set = <T extends ExcalidrawElement>(
element: T,
shape: T["type"] extends keyof ElementShapes
? ElementShapes[T["type"]]
: Drawable,
) => ShapeCache.cache.set(element, shape);
public static delete = (element: ExcalidrawElement) =>
ShapeCache.cache.delete(element);
public static destroy = () => {
ShapeCache.cache = new WeakMap();
};
/**
* Generates & caches shape for element if not already cached, otherwise
* returns cached shape.
*/
public static generateElementShape = <
T extends Exclude<ExcalidrawElement, ExcalidrawSelectionElement>,
>(
element: T,
renderConfig: {
isExporting: boolean;
canvasBackgroundColor: AppState["viewBackgroundColor"];
embedsValidationStatus: EmbedsValidationStatus;
} | null,
) => {
// when exporting, always regenerated to guarantee the latest shape
const cachedShape = renderConfig?.isExporting
? undefined
: ShapeCache.get(element);
// `null` indicates no rc shape applicable for this element type,
// but it's considered a valid cache value (= do not regenerate)
if (cachedShape !== undefined) {
return cachedShape;
}
elementWithCanvasCache.delete(element);
const shape = generateElementShape(
element,
ShapeCache.rg,
renderConfig || {
isExporting: false,
canvasBackgroundColor: COLOR_PALETTE.white,
embedsValidationStatus: null,
},
) as T["type"] extends keyof ElementShapes
? ElementShapes[T["type"]]
: Drawable | null;
ShapeCache.cache.set(element, shape);
return shape;
};
}
const getDashArrayDashed = (strokeWidth: number) => [8, 8 + strokeWidth];
const getDashArrayDotted = (strokeWidth: number) => [1.5, 6 + strokeWidth];
function adjustRoughness(element: ExcalidrawElement): number {
const roughness = element.roughness;
const maxSize = Math.max(element.width, element.height);
const minSize = Math.min(element.width, element.height);
// don't reduce roughness if
if (
// both sides relatively big
(minSize >= 20 && maxSize >= 50) ||
// is round & both sides above 15px
(minSize >= 15 &&
!!element.roundness &&
canChangeRoundness(element.type)) ||
// relatively long linear element
(isLinearElement(element) && maxSize >= 50)
) {
return roughness;
}
return Math.min(roughness / (maxSize < 10 ? 3 : 2), 2.5);
}
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: adjustRoughness(element),
stroke: element.strokeColor,
preserveVertices:
continuousPath || element.roughness < ROUGHNESS.cartoonist,
};
switch (element.type) {
case "rectangle":
case "iframe":
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 modifyIframeLikeForRoughOptions = (
element: NonDeletedExcalidrawElement,
isExporting: boolean,
embedsValidationStatus: EmbedsValidationStatus | null,
) => {
if (
isIframeLikeElement(element) &&
(isExporting ||
(isEmbeddableElement(element) &&
embedsValidationStatus?.get(element.id) !== true)) &&
isTransparent(element.backgroundColor) &&
isTransparent(element.strokeColor)
) {
return {
...element,
roughness: 0,
backgroundColor: "#d3d3d3",
fillStyle: "solid",
} as const;
} else if (isIframeElement(element)) {
return {
...element,
strokeColor: isTransparent(element.strokeColor)
? "#000000"
: element.strokeColor,
backgroundColor: isTransparent(element.backgroundColor)
? "#f4f4f6"
: element.backgroundColor,
};
}
return element;
};
const getArrowheadShapes = (
element: ExcalidrawLinearElement,
shape: Drawable[],
position: "start" | "end",
arrowhead: Arrowhead,
generator: RoughGenerator,
options: Options,
canvasBackgroundColor: string,
) => {
const arrowheadPoints = getArrowheadPoints(
element,
shape,
position,
arrowhead,
);
if (arrowheadPoints === null) {
return [];
}
const generateCrowfootOne = (
arrowheadPoints: number[] | null,
options: Options,
) => {
if (arrowheadPoints === null) {
return [];
}
const [, , x3, y3, x4, y4] = arrowheadPoints;
return [generator.line(x3, y3, x4, y4, options)];
};
switch (arrowhead) {
case "dot":
case "circle":
case "circle_outline": {
const [x, y, diameter] = arrowheadPoints;
// always use solid stroke for arrowhead
delete options.strokeLineDash;
return [
generator.circle(x, y, diameter, {
...options,
fill:
arrowhead === "circle_outline"
? canvasBackgroundColor
: element.strokeColor,
fillStyle: "solid",
stroke: element.strokeColor,
roughness: Math.min(0.5, options.roughness || 0),
}),
];
}
case "triangle":
case "triangle_outline": {
const [x, y, x2, y2, x3, y3] = arrowheadPoints;
// always use solid stroke for arrowhead
delete options.strokeLineDash;
return [
generator.polygon(
[
[x, y],
[x2, y2],
[x3, y3],
[x, y],
],
{
...options,
fill:
arrowhead === "triangle_outline"
? canvasBackgroundColor
: element.strokeColor,
fillStyle: "solid",
roughness: Math.min(1, options.roughness || 0),
},
),
];
}
case "diamond":
case "diamond_outline": {
const [x, y, x2, y2, x3, y3, x4, y4] = arrowheadPoints;
// always use solid stroke for arrowhead
delete options.strokeLineDash;
return [
generator.polygon(
[
[x, y],
[x2, y2],
[x3, y3],
[x4, y4],
[x, y],
],
{
...options,
fill:
arrowhead === "diamond_outline"
? canvasBackgroundColor
: element.strokeColor,
fillStyle: "solid",
roughness: Math.min(1, options.roughness || 0),
},
),
];
}
case "crowfoot_one":
return generateCrowfootOne(arrowheadPoints, options);
case "bar":
case "arrow":
case "crowfoot_many":
case "crowfoot_one_or_many":
default: {
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;
}
options.roughness = Math.min(1, options.roughness || 0);
return [
generator.line(x3, y3, x2, y2, options),
generator.line(x4, y4, x2, y2, options),
...(arrowhead === "crowfoot_one_or_many"
? generateCrowfootOne(
getArrowheadPoints(element, shape, position, "crowfoot_one"),
options,
)
: []),
];
}
}
};
export const generateLinearCollisionShape = (
element: ExcalidrawLinearElement | ExcalidrawFreeDrawElement,
) => {
const generator = new RoughGenerator();
const options: Options = {
seed: element.seed,
disableMultiStroke: true,
disableMultiStrokeFill: true,
roughness: 0,
preserveVertices: true,
};
const center = getCenterForBounds(
// Need a non-rotated center point
element.points.reduce(
(acc, point) => {
return [
Math.min(element.x + point[0], acc[0]),
Math.min(element.y + point[1], acc[1]),
Math.max(element.x + point[0], acc[2]),
Math.max(element.y + point[1], acc[3]),
];
},
[Infinity, Infinity, -Infinity, -Infinity],
),
);
switch (element.type) {
case "line":
case "arrow": {
// 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
: [pointFrom<LocalPoint>(0, 0)];
if (isElbowArrow(element)) {
return generator.path(generateElbowArrowShape(points, 16), options)
.sets[0].ops;
} else if (!element.roundness) {
return points.map((point, idx) => {
const p = pointRotateRads(
pointFrom<GlobalPoint>(element.x + point[0], element.y + point[1]),
center,
element.angle,
);
return {
op: idx === 0 ? "move" : "lineTo",
data: pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
};
});
}
return generator
.curve(points as unknown as RoughPoint[], options)
.sets[0].ops.slice(0, element.points.length)
.map((op, i) => {
if (i === 0) {
const p = pointRotateRads<GlobalPoint>(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
);
return {
op: "move",
data: pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
};
}
return {
op: "bcurveTo",
data: [
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[2],
element.y + op.data[3],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[4],
element.y + op.data[5],
),
center,
element.angle,
),
]
.map((p) =>
pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
)
.flat(),
};
});
}
case "freedraw": {
if (element.points.length < 2) {
return [];
}
const simplifiedPoints = simplify(
element.points as Mutable<LocalPoint[]>,
0.75,
);
return generator
.curve(simplifiedPoints as [number, number][], options)
.sets[0].ops.slice(0, element.points.length)
.map((op, i) => {
if (i === 0) {
const p = pointRotateRads<GlobalPoint>(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
);
return {
op: "move",
data: pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
};
}
return {
op: "bcurveTo",
data: [
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[2],
element.y + op.data[3],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[4],
element.y + op.data[5],
),
center,
element.angle,
),
]
.map((p) =>
pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
)
.flat(),
};
});
}
}
};
/**
* Generates the roughjs shape for given element.
*
* Low-level. Use `ShapeCache.generateElementShape` instead.
*
* @private
*/
const generateElementShape = (
element: Exclude<NonDeletedExcalidrawElement, ExcalidrawSelectionElement>,
generator: RoughGenerator,
{
isExporting,
canvasBackgroundColor,
embedsValidationStatus,
}: {
isExporting: boolean;
canvasBackgroundColor: string;
embedsValidationStatus: EmbedsValidationStatus | null;
},
): Drawable | Drawable[] | null => {
switch (element.type) {
case "rectangle":
case "iframe":
case "embeddable": {
let shape: ElementShapes[typeof element.type];
// 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(
modifyIframeLikeForRoughOptions(
element,
isExporting,
embedsValidationStatus,
),
true,
),
);
} else {
shape = generator.rectangle(
0,
0,
element.width,
element.height,
generateRoughOptions(
modifyIframeLikeForRoughOptions(
element,
isExporting,
embedsValidationStatus,
),
false,
),
);
}
return shape;
}
case "diamond": {
let shape: ElementShapes[typeof element.type];
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),
);
}
return shape;
}
case "ellipse": {
const shape: ElementShapes[typeof element.type] = generator.ellipse(
element.width / 2,
element.height / 2,
element.width,
element.height,
generateRoughOptions(element),
);
return shape;
}
case "line":
case "arrow": {
let shape: ElementShapes[typeof element.type];
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
: [pointFrom<LocalPoint>(0, 0)];
if (isElbowArrow(element)) {
// NOTE (mtolmacs): Temporary fix for extremely big arrow shapes
if (
!points.every(
(point) => Math.abs(point[0]) <= 1e6 && Math.abs(point[1]) <= 1e6,
)
) {
console.error(
`Elbow arrow with extreme point positions detected. Arrow not rendered.`,
element.id,
JSON.stringify(points),
);
shape = [];
} else {
shape = [
generator.path(
generateElbowArrowShape(points, 16),
generateRoughOptions(element, true),
),
];
}
} else if (!element.roundness) {
// curve is always the first element
// this simplifies finding the curve for an element
if (options.fill) {
shape = [
generator.polygon(points as unknown as RoughPoint[], options),
];
} else {
shape = [
generator.linearPath(points as unknown as RoughPoint[], options),
];
}
} else {
shape = [generator.curve(points as unknown as RoughPoint[], options)];
}
// add lines only in arrow
if (element.type === "arrow") {
const { startArrowhead = null, endArrowhead = "arrow" } = element;
if (startArrowhead !== null) {
const shapes = getArrowheadShapes(
element,
shape,
"start",
startArrowhead,
generator,
options,
canvasBackgroundColor,
);
shape.push(...shapes);
}
if (endArrowhead !== null) {
if (endArrowhead === undefined) {
// Hey, we have an old arrow here!
}
const shapes = getArrowheadShapes(
element,
shape,
"end",
endArrowhead,
generator,
options,
canvasBackgroundColor,
);
shape.push(...shapes);
}
}
return shape;
}
case "freedraw": {
let shape: ElementShapes[typeof element.type];
generateFreeDrawShape(element);
if (isPathALoop(element.points)) {
// generate rough polygon to fill freedraw shape
const simplifiedPoints = simplify(
element.points as Mutable<LocalPoint[]>,
0.75,
);
shape = generator.curve(simplifiedPoints as [number, number][], {
...generateRoughOptions(element),
stroke: "none",
});
} else {
shape = null;
}
return shape;
}
case "frame":
case "magicframe":
case "text":
case "image": {
const shape: ElementShapes[typeof element.type] = null;
// we return (and cache) `null` to make sure we don't regenerate
// `element.canvas` on rerenders
return shape;
}
default: {
assertNever(
element,
`generateElementShape(): Unimplemented type ${(element as any)?.type}`,
);
return null;
}
}
};
const generateElbowArrowShape = (
points: readonly LocalPoint[],
radius: number,
) => {
const subpoints = [] as [number, number][];
for (let i = 1; i < points.length - 1; i += 1) {
const prev = points[i - 1];
const next = points[i + 1];
const point = points[i];
const prevIsHorizontal = headingForPointIsHorizontal(point, prev);
const nextIsHorizontal = headingForPointIsHorizontal(next, point);
const corner = Math.min(
radius,
pointDistance(points[i], next) / 2,
pointDistance(points[i], prev) / 2,
);
if (prevIsHorizontal) {
if (prev[0] < point[0]) {
// LEFT
subpoints.push([points[i][0] - corner, points[i][1]]);
} else {
// RIGHT
subpoints.push([points[i][0] + corner, points[i][1]]);
}
} else if (prev[1] < point[1]) {
// UP
subpoints.push([points[i][0], points[i][1] - corner]);
} else {
subpoints.push([points[i][0], points[i][1] + corner]);
}
subpoints.push(points[i] as [number, number]);
if (nextIsHorizontal) {
if (next[0] < point[0]) {
// LEFT
subpoints.push([points[i][0] - corner, points[i][1]]);
} else {
// RIGHT
subpoints.push([points[i][0] + corner, points[i][1]]);
}
} else if (next[1] < point[1]) {
// UP
subpoints.push([points[i][0], points[i][1] - corner]);
} else {
// DOWN
subpoints.push([points[i][0], points[i][1] + corner]);
}
}
const d = [`M ${points[0][0]} ${points[0][1]}`];
for (let i = 0; i < subpoints.length; i += 3) {
d.push(`L ${subpoints[i][0]} ${subpoints[i][1]}`);
d.push(
`Q ${subpoints[i + 1][0]} ${subpoints[i + 1][1]}, ${
subpoints[i + 2][0]
} ${subpoints[i + 2][1]}`,
);
}
d.push(`L ${points[points.length - 1][0]} ${points[points.length - 1][1]}`);
return d.join(" ");
};
/**
* get the pure geometric shape of an excalidraw elementw
* which is then used for hit detection
*/
export const getElementShape = <Point extends GlobalPoint | LocalPoint>(
element: ExcalidrawElement,
elementsMap: ElementsMap,
): GeometricShape<Point> => {
switch (element.type) {
case "rectangle":
case "diamond":
case "frame":
case "magicframe":
case "embeddable":
case "image":
case "iframe":
case "text":
case "selection":
return getPolygonShape(element);
case "arrow":
case "line": {
const roughShape =
ShapeCache.get(element)?.[0] ??
ShapeCache.generateElementShape(element, null)[0];
const [, , , , cx, cy] = getElementAbsoluteCoords(element, elementsMap);
return shouldTestInside(element)
? getClosedCurveShape<Point>(
element,
roughShape,
pointFrom<Point>(element.x, element.y),
element.angle,
pointFrom(cx, cy),
)
: getCurveShape<Point>(
roughShape,
pointFrom<Point>(element.x, element.y),
element.angle,
pointFrom(cx, cy),
);
}
case "ellipse":
return getEllipseShape(element);
case "freedraw": {
const [, , , , cx, cy] = getElementAbsoluteCoords(element, elementsMap);
return getFreedrawShape(
element,
pointFrom(cx, cy),
shouldTestInside(element),
);
}
}
};
export const toggleLinePolygonState = (
element: ExcalidrawLineElement,
nextPolygonState: boolean,
): {
polygon: ExcalidrawLineElement["polygon"];
points: ExcalidrawLineElement["points"];
} | null => {
const updatedPoints = [...element.points];
if (nextPolygonState) {
if (!canBecomePolygon(element.points)) {
return null;
}
const firstPoint = updatedPoints[0];
const lastPoint = updatedPoints[updatedPoints.length - 1];
const distance = Math.hypot(
firstPoint[0] - lastPoint[0],
firstPoint[1] - lastPoint[1],
);
if (
distance > LINE_POLYGON_POINT_MERGE_DISTANCE ||
updatedPoints.length < 4
) {
updatedPoints.push(pointFrom(firstPoint[0], firstPoint[1]));
} else {
updatedPoints[updatedPoints.length - 1] = pointFrom(
firstPoint[0],
firstPoint[1],
);
}
}
// TODO: satisfies ElementUpdate<ExcalidrawLineElement>
const ret = {
polygon: nextPolygonState,
points: updatedPoints,
};
return ret;
};