html2canvas/src/render/canvas/canvas-renderer.ts

934 lines
38 KiB
TypeScript

import {ElementPaint, parseStackingContexts, StackingContext} from '../stacking-context';
import {asString, Color, isTransparent} from '../../css/types/color';
import {Logger} from '../../core/logger';
import {ElementContainer} from '../../dom/element-container';
import {BORDER_STYLE} from '../../css/property-descriptors/border-style';
import {CSSParsedDeclaration} from '../../css/index';
import {TextContainer} from '../../dom/text-container';
import {Path, transformPath} from '../path';
import {BACKGROUND_CLIP} from '../../css/property-descriptors/background-clip';
import {BoundCurves, calculateBorderBoxPath, calculateContentBoxPath, calculatePaddingBoxPath} from '../bound-curves';
import {BezierCurve, isBezierCurve} from '../bezier-curve';
import {Vector} from '../vector';
import {CSSImageType, CSSURLImage, isLinearGradient, isRadialGradient} from '../../css/types/image';
import {
parsePathForBorder,
parsePathForBorderDoubleInner,
parsePathForBorderDoubleOuter,
parsePathForBorderStroke
} from '../border';
import {Cache} from '../../core/cache-storage';
import {calculateBackgroundRendering, getBackgroundValueForIndex} from '../background';
import {isDimensionToken} from '../../css/syntax/parser';
import {TextBounds} from '../../css/layout/text';
import {fromCodePoint, toCodePoints} from 'css-line-break';
import {ImageElementContainer} from '../../dom/replaced-elements/image-element-container';
import {contentBox} from '../box-sizing';
import {CanvasElementContainer} from '../../dom/replaced-elements/canvas-element-container';
import {SVGElementContainer} from '../../dom/replaced-elements/svg-element-container';
import {ReplacedElementContainer} from '../../dom/replaced-elements/index';
import {EffectTarget, IElementEffect, isClipEffect, isOpacityEffect, isTransformEffect} from '../effects';
import {contains} from '../../core/bitwise';
import {calculateGradientDirection, calculateRadius, processColorStops} from '../../css/types/functions/gradient';
import {FIFTY_PERCENT, getAbsoluteValue} from '../../css/types/length-percentage';
import {TEXT_DECORATION_LINE} from '../../css/property-descriptors/text-decoration-line';
import {FontMetrics} from '../font-metrics';
import {DISPLAY} from '../../css/property-descriptors/display';
import {Bounds} from '../../css/layout/bounds';
import {LIST_STYLE_TYPE} from '../../css/property-descriptors/list-style-type';
import {computeLineHeight} from '../../css/property-descriptors/line-height';
import {CHECKBOX, INPUT_COLOR, InputElementContainer, RADIO} from '../../dom/replaced-elements/input-element-container';
import {TEXT_ALIGN} from '../../css/property-descriptors/text-align';
import {TextareaElementContainer} from '../../dom/elements/textarea-element-container';
import {SelectElementContainer} from '../../dom/elements/select-element-container';
import {IFrameElementContainer} from '../../dom/replaced-elements/iframe-element-container';
import {TextShadow} from '../../css/property-descriptors/text-shadow';
export type RenderConfigurations = RenderOptions & {
backgroundColor: Color | null;
};
export interface RenderOptions {
id: string;
scale: number;
canvas?: HTMLCanvasElement;
x: number;
y: number;
scrollX: number;
scrollY: number;
width: number;
height: number;
windowWidth: number;
windowHeight: number;
cache: Cache;
}
const MASK_OFFSET = 10000;
export class CanvasRenderer {
canvas: HTMLCanvasElement;
ctx: CanvasRenderingContext2D;
options: RenderConfigurations;
private readonly _activeEffects: IElementEffect[] = [];
private readonly fontMetrics: FontMetrics;
constructor(options: RenderConfigurations) {
this.canvas = options.canvas ? options.canvas : document.createElement('canvas');
this.ctx = this.canvas.getContext('2d') as CanvasRenderingContext2D;
this.options = options;
if (!options.canvas) {
this.canvas.width = Math.floor(options.width * options.scale);
this.canvas.height = Math.floor(options.height * options.scale);
this.canvas.style.width = `${options.width}px`;
this.canvas.style.height = `${options.height}px`;
}
this.fontMetrics = new FontMetrics(document);
this.ctx.scale(this.options.scale, this.options.scale);
this.ctx.translate(-options.x + options.scrollX, -options.y + options.scrollY);
this.ctx.textBaseline = 'bottom';
this._activeEffects = [];
Logger.getInstance(options.id).debug(
`Canvas renderer initialized (${options.width}x${options.height} at ${options.x},${options.y}) with scale ${options.scale}`
);
}
applyEffects(effects: IElementEffect[], target: EffectTarget): void {
while (this._activeEffects.length) {
this.popEffect();
}
effects.filter((effect) => contains(effect.target, target)).forEach((effect) => this.applyEffect(effect));
}
applyEffect(effect: IElementEffect): void {
this.ctx.save();
if (isOpacityEffect(effect)) {
this.ctx.globalAlpha = effect.opacity;
}
if (isTransformEffect(effect)) {
this.ctx.translate(effect.offsetX, effect.offsetY);
this.ctx.transform(
effect.matrix[0],
effect.matrix[1],
effect.matrix[2],
effect.matrix[3],
effect.matrix[4],
effect.matrix[5]
);
this.ctx.translate(-effect.offsetX, -effect.offsetY);
}
if (isClipEffect(effect)) {
this.path(effect.path);
this.ctx.clip();
}
this._activeEffects.push(effect);
}
popEffect(): void {
this._activeEffects.pop();
this.ctx.restore();
}
async renderStack(stack: StackingContext): Promise<void> {
const styles = stack.element.container.styles;
if (styles.isVisible()) {
await this.renderStackContent(stack);
}
}
async renderNode(paint: ElementPaint): Promise<void> {
if (paint.container.styles.isVisible()) {
await this.renderNodeBackgroundAndBorders(paint);
await this.renderNodeContent(paint);
}
}
renderTextWithLetterSpacing(text: TextBounds, letterSpacing: number, baseline: number): void {
if (letterSpacing === 0) {
this.ctx.fillText(text.text, text.bounds.left, text.bounds.top + baseline);
} else {
const letters = toCodePoints(text.text).map((i) => fromCodePoint(i));
letters.reduce((left, letter) => {
this.ctx.fillText(letter, left, text.bounds.top + baseline);
return left + this.ctx.measureText(letter).width;
}, text.bounds.left);
}
}
private createFontStyle(styles: CSSParsedDeclaration): string[] {
const fontVariant = styles.fontVariant
.filter((variant) => variant === 'normal' || variant === 'small-caps')
.join('');
const fontFamily = styles.fontFamily.join(', ');
const fontSize = isDimensionToken(styles.fontSize)
? `${styles.fontSize.number}${styles.fontSize.unit}`
: `${styles.fontSize.number}px`;
return [
[styles.fontStyle, fontVariant, styles.fontWeight, fontSize, fontFamily].join(' '),
fontFamily,
fontSize
];
}
async renderTextNode(text: TextContainer, styles: CSSParsedDeclaration): Promise<void> {
const [font, fontFamily, fontSize] = this.createFontStyle(styles);
this.ctx.font = font;
this.ctx.textBaseline = 'alphabetic';
const {baseline, middle} = this.fontMetrics.getMetrics(fontFamily, fontSize);
text.textBounds.forEach((text) => {
this.ctx.fillStyle = asString(styles.color);
this.renderTextWithLetterSpacing(text, styles.letterSpacing, baseline);
const textShadows: TextShadow = styles.textShadow;
if (textShadows.length && text.text.trim().length) {
textShadows
.slice(0)
.reverse()
.forEach((textShadow) => {
this.ctx.shadowColor = asString(textShadow.color);
this.ctx.shadowOffsetX = textShadow.offsetX.number * this.options.scale;
this.ctx.shadowOffsetY = textShadow.offsetY.number * this.options.scale;
this.ctx.shadowBlur = textShadow.blur.number;
this.ctx.fillText(text.text, text.bounds.left, text.bounds.top + text.bounds.height);
});
this.ctx.shadowColor = '';
this.ctx.shadowOffsetX = 0;
this.ctx.shadowOffsetY = 0;
this.ctx.shadowBlur = 0;
}
if (styles.textDecorationLine.length) {
this.ctx.fillStyle = asString(styles.textDecorationColor || styles.color);
styles.textDecorationLine.forEach((textDecorationLine) => {
switch (textDecorationLine) {
case TEXT_DECORATION_LINE.UNDERLINE:
// Draws a line at the baseline of the font
// TODO As some browsers display the line as more than 1px if the font-size is big,
// need to take that into account both in position and size
this.ctx.fillRect(
text.bounds.left,
Math.round(text.bounds.top + baseline),
text.bounds.width,
1
);
break;
case TEXT_DECORATION_LINE.OVERLINE:
this.ctx.fillRect(text.bounds.left, Math.round(text.bounds.top), text.bounds.width, 1);
break;
case TEXT_DECORATION_LINE.LINE_THROUGH:
// TODO try and find exact position for line-through
this.ctx.fillRect(
text.bounds.left,
Math.ceil(text.bounds.top + middle),
text.bounds.width,
1
);
break;
}
});
}
});
}
renderReplacedElement(
container: ReplacedElementContainer,
curves: BoundCurves,
image: HTMLImageElement | HTMLCanvasElement
): void {
if (image && container.intrinsicWidth > 0 && container.intrinsicHeight > 0) {
const box = contentBox(container);
const path = calculatePaddingBoxPath(curves);
this.path(path);
this.ctx.save();
this.ctx.clip();
this.ctx.drawImage(
image,
0,
0,
container.intrinsicWidth,
container.intrinsicHeight,
box.left,
box.top,
box.width,
box.height
);
this.ctx.restore();
}
}
async renderNodeContent(paint: ElementPaint): Promise<void> {
this.applyEffects(paint.effects, EffectTarget.CONTENT);
const container = paint.container;
const curves = paint.curves;
const styles = container.styles;
for (const child of container.textNodes) {
await this.renderTextNode(child, styles);
}
if (container instanceof ImageElementContainer) {
try {
const image = await this.options.cache.match(container.src);
this.renderReplacedElement(container, curves, image);
} catch (e) {
Logger.getInstance(this.options.id).error(`Error loading image ${container.src}`);
}
}
if (container instanceof CanvasElementContainer) {
this.renderReplacedElement(container, curves, container.canvas);
}
if (container instanceof SVGElementContainer) {
try {
const image = await this.options.cache.match(container.svg);
this.renderReplacedElement(container, curves, image);
} catch (e) {
Logger.getInstance(this.options.id).error(`Error loading svg ${container.svg.substring(0, 255)}`);
}
}
if (container instanceof IFrameElementContainer && container.tree) {
const iframeRenderer = new CanvasRenderer({
id: this.options.id,
scale: this.options.scale,
backgroundColor: container.backgroundColor,
x: 0,
y: 0,
scrollX: 0,
scrollY: 0,
width: container.width,
height: container.height,
cache: this.options.cache,
windowWidth: container.width,
windowHeight: container.height
});
const canvas = await iframeRenderer.render(container.tree);
if (container.width && container.height) {
this.ctx.drawImage(
canvas,
0,
0,
container.width,
container.height,
container.bounds.left,
container.bounds.top,
container.bounds.width,
container.bounds.height
);
}
}
if (container instanceof InputElementContainer) {
const size = Math.min(container.bounds.width, container.bounds.height);
if (container.type === CHECKBOX) {
if (container.checked) {
this.ctx.save();
this.path([
new Vector(container.bounds.left + size * 0.39363, container.bounds.top + size * 0.79),
new Vector(container.bounds.left + size * 0.16, container.bounds.top + size * 0.5549),
new Vector(container.bounds.left + size * 0.27347, container.bounds.top + size * 0.44071),
new Vector(container.bounds.left + size * 0.39694, container.bounds.top + size * 0.5649),
new Vector(container.bounds.left + size * 0.72983, container.bounds.top + size * 0.23),
new Vector(container.bounds.left + size * 0.84, container.bounds.top + size * 0.34085),
new Vector(container.bounds.left + size * 0.39363, container.bounds.top + size * 0.79)
]);
this.ctx.fillStyle = asString(INPUT_COLOR);
this.ctx.fill();
this.ctx.restore();
}
} else if (container.type === RADIO) {
if (container.checked) {
this.ctx.save();
this.ctx.beginPath();
this.ctx.arc(
container.bounds.left + size / 2,
container.bounds.top + size / 2,
size / 4,
0,
Math.PI * 2,
true
);
this.ctx.fillStyle = asString(INPUT_COLOR);
this.ctx.fill();
this.ctx.restore();
}
}
}
if (isTextInputElement(container) && container.value.length) {
const [fontFamily, fontSize] = this.createFontStyle(styles);
const {baseline} = this.fontMetrics.getMetrics(fontFamily, fontSize);
this.ctx.font = fontFamily;
this.ctx.fillStyle = asString(styles.color);
this.ctx.textBaseline = 'middle';
this.ctx.textAlign = canvasTextAlign(container.styles.textAlign);
const bounds = contentBox(container);
let x = 0;
switch (container.styles.textAlign) {
case TEXT_ALIGN.CENTER:
x += bounds.width / 2;
break;
case TEXT_ALIGN.RIGHT:
x += bounds.width;
break;
}
const textBounds = bounds.add(x, 0, 0, -bounds.height / 2 + 1);
this.ctx.save();
this.path([
new Vector(bounds.left, bounds.top),
new Vector(bounds.left + bounds.width, bounds.top),
new Vector(bounds.left + bounds.width, bounds.top + bounds.height),
new Vector(bounds.left, bounds.top + bounds.height)
]);
this.ctx.clip();
this.renderTextWithLetterSpacing(
new TextBounds(container.value, textBounds),
styles.letterSpacing,
baseline
);
this.ctx.restore();
this.ctx.textBaseline = 'bottom';
this.ctx.textAlign = 'left';
}
if (contains(container.styles.display, DISPLAY.LIST_ITEM)) {
if (container.styles.listStyleImage !== null) {
const img = container.styles.listStyleImage;
if (img.type === CSSImageType.URL) {
let image;
const url = (img as CSSURLImage).url;
try {
image = await this.options.cache.match(url);
this.ctx.drawImage(image, container.bounds.left - (image.width + 10), container.bounds.top);
} catch (e) {
Logger.getInstance(this.options.id).error(`Error loading list-style-image ${url}`);
}
}
} else if (paint.listValue && container.styles.listStyleType !== LIST_STYLE_TYPE.NONE) {
const [fontFamily, fontSize] = this.createFontStyle(styles);
this.ctx.font = fontFamily;
this.ctx.fillStyle = asString(styles.color);
this.ctx.textBaseline = 'middle';
this.ctx.textAlign = 'right';
const bounds = new Bounds(
container.bounds.left,
container.bounds.top + getAbsoluteValue(container.styles.paddingTop, container.bounds.width),
container.bounds.width,
computeLineHeight(styles.lineHeight, styles.fontSize.number) / 2 + 1
);
const {baseline} = this.fontMetrics.getMetrics(fontFamily, fontSize);
this.renderTextWithLetterSpacing(
new TextBounds(paint.listValue, bounds),
styles.letterSpacing,
baseline
);
this.ctx.textBaseline = 'bottom';
this.ctx.textAlign = 'left';
}
}
}
async renderStackContent(stack: StackingContext): Promise<void> {
// https://www.w3.org/TR/css-position-3/#painting-order
// 1. the background and borders of the element forming the stacking context.
await this.renderNodeBackgroundAndBorders(stack.element);
// 2. the child stacking contexts with negative stack levels (most negative first).
for (const child of stack.negativeZIndex) {
await this.renderStack(child);
}
// 3. For all its in-flow, non-positioned, block-level descendants in tree order:
await this.renderNodeContent(stack.element);
for (const child of stack.nonInlineLevel) {
await this.renderNode(child);
}
// 4. All non-positioned floating descendants, in tree order. For each one of these,
// treat the element as if it created a new stacking context, but any positioned descendants and descendants
// which actually create a new stacking context should be considered part of the parent stacking context,
// not this new one.
for (const child of stack.nonPositionedFloats) {
await this.renderStack(child);
}
// 5. the in-flow, inline-level, non-positioned descendants, including inline tables and inline blocks.
for (const child of stack.nonPositionedInlineLevel) {
await this.renderStack(child);
}
for (const child of stack.inlineLevel) {
await this.renderNode(child);
}
// 6. All positioned, opacity or transform descendants, in tree order that fall into the following categories:
// All positioned descendants with 'z-index: auto' or 'z-index: 0', in tree order.
// For those with 'z-index: auto', treat the element as if it created a new stacking context,
// but any positioned descendants and descendants which actually create a new stacking context should be
// considered part of the parent stacking context, not this new one. For those with 'z-index: 0',
// treat the stacking context generated atomically.
//
// All opacity descendants with opacity less than 1
//
// All transform descendants with transform other than none
for (const child of stack.zeroOrAutoZIndexOrTransformedOrOpacity) {
await this.renderStack(child);
}
// 7. Stacking contexts formed by positioned descendants with z-indices greater than or equal to 1 in z-index
// order (smallest first) then tree order.
for (const child of stack.positiveZIndex) {
await this.renderStack(child);
}
}
mask(paths: Path[]): void {
this.ctx.beginPath();
this.ctx.moveTo(0, 0);
this.ctx.lineTo(this.canvas.width, 0);
this.ctx.lineTo(this.canvas.width, this.canvas.height);
this.ctx.lineTo(0, this.canvas.height);
this.ctx.lineTo(0, 0);
this.formatPath(paths.slice(0).reverse());
this.ctx.closePath();
}
path(paths: Path[]): void {
this.ctx.beginPath();
this.formatPath(paths);
this.ctx.closePath();
}
formatPath(paths: Path[]): void {
paths.forEach((point, index) => {
const start: Vector = isBezierCurve(point) ? point.start : point;
if (index === 0) {
this.ctx.moveTo(start.x, start.y);
} else {
this.ctx.lineTo(start.x, start.y);
}
if (isBezierCurve(point)) {
this.ctx.bezierCurveTo(
point.startControl.x,
point.startControl.y,
point.endControl.x,
point.endControl.y,
point.end.x,
point.end.y
);
}
});
}
renderRepeat(path: Path[], pattern: CanvasPattern | CanvasGradient, offsetX: number, offsetY: number): void {
this.path(path);
this.ctx.fillStyle = pattern;
this.ctx.translate(offsetX, offsetY);
this.ctx.fill();
this.ctx.translate(-offsetX, -offsetY);
}
resizeImage(image: HTMLImageElement, width: number, height: number): HTMLCanvasElement | HTMLImageElement {
if (image.width === width && image.height === height) {
return image;
}
const canvas = (this.canvas.ownerDocument as Document).createElement('canvas');
canvas.width = Math.max(1, width);
canvas.height = Math.max(1, height);
const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
ctx.drawImage(image, 0, 0, image.width, image.height, 0, 0, width, height);
return canvas;
}
async renderBackgroundImage(container: ElementContainer): Promise<void> {
let index = container.styles.backgroundImage.length - 1;
for (const backgroundImage of container.styles.backgroundImage.slice(0).reverse()) {
if (backgroundImage.type === CSSImageType.URL) {
let image;
const url = (backgroundImage as CSSURLImage).url;
try {
image = await this.options.cache.match(url);
} catch (e) {
Logger.getInstance(this.options.id).error(`Error loading background-image ${url}`);
}
if (image) {
const [path, x, y, width, height] = calculateBackgroundRendering(container, index, [
image.width,
image.height,
image.width / image.height
]);
const pattern = this.ctx.createPattern(
this.resizeImage(image, width, height),
'repeat'
) as CanvasPattern;
this.renderRepeat(path, pattern, x, y);
}
} else if (isLinearGradient(backgroundImage)) {
const [path, x, y, width, height] = calculateBackgroundRendering(container, index, [null, null, null]);
const [lineLength, x0, x1, y0, y1] = calculateGradientDirection(backgroundImage.angle, width, height);
const canvas = document.createElement('canvas');
canvas.width = width;
canvas.height = height;
const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
const gradient = ctx.createLinearGradient(x0, y0, x1, y1);
processColorStops(backgroundImage.stops, lineLength).forEach((colorStop) =>
gradient.addColorStop(colorStop.stop, asString(colorStop.color))
);
ctx.fillStyle = gradient;
ctx.fillRect(0, 0, width, height);
if (width > 0 && height > 0) {
const pattern = this.ctx.createPattern(canvas, 'repeat') as CanvasPattern;
this.renderRepeat(path, pattern, x, y);
}
} else if (isRadialGradient(backgroundImage)) {
const [path, left, top, width, height] = calculateBackgroundRendering(container, index, [
null,
null,
null
]);
const position = backgroundImage.position.length === 0 ? [FIFTY_PERCENT] : backgroundImage.position;
const x = getAbsoluteValue(position[0], width);
const y = getAbsoluteValue(position[position.length - 1], height);
const [rx, ry] = calculateRadius(backgroundImage, x, y, width, height);
if (rx > 0 && rx > 0) {
const radialGradient = this.ctx.createRadialGradient(left + x, top + y, 0, left + x, top + y, rx);
processColorStops(backgroundImage.stops, rx * 2).forEach((colorStop) =>
radialGradient.addColorStop(colorStop.stop, asString(colorStop.color))
);
this.path(path);
this.ctx.fillStyle = radialGradient;
if (rx !== ry) {
// transforms for elliptical radial gradient
const midX = container.bounds.left + 0.5 * container.bounds.width;
const midY = container.bounds.top + 0.5 * container.bounds.height;
const f = ry / rx;
const invF = 1 / f;
this.ctx.save();
this.ctx.translate(midX, midY);
this.ctx.transform(1, 0, 0, f, 0, 0);
this.ctx.translate(-midX, -midY);
this.ctx.fillRect(left, invF * (top - midY) + midY, width, height * invF);
this.ctx.restore();
} else {
this.ctx.fill();
}
}
}
index--;
}
}
async renderSolidBorder(color: Color, side: number, curvePoints: BoundCurves): Promise<void> {
this.path(parsePathForBorder(curvePoints, side));
this.ctx.fillStyle = asString(color);
this.ctx.fill();
}
async renderDoubleBorder(color: Color, width: number, side: number, curvePoints: BoundCurves): Promise<void> {
if (width < 3) {
await this.renderSolidBorder(color, side, curvePoints);
return;
}
const outerPaths = parsePathForBorderDoubleOuter(curvePoints, side);
this.path(outerPaths);
this.ctx.fillStyle = asString(color);
this.ctx.fill();
const innerPaths = parsePathForBorderDoubleInner(curvePoints, side);
this.path(innerPaths);
this.ctx.fill();
}
async renderNodeBackgroundAndBorders(paint: ElementPaint): Promise<void> {
this.applyEffects(paint.effects, EffectTarget.BACKGROUND_BORDERS);
const styles = paint.container.styles;
const hasBackground = !isTransparent(styles.backgroundColor) || styles.backgroundImage.length;
const borders = [
{style: styles.borderTopStyle, color: styles.borderTopColor, width: styles.borderTopWidth},
{style: styles.borderRightStyle, color: styles.borderRightColor, width: styles.borderRightWidth},
{style: styles.borderBottomStyle, color: styles.borderBottomColor, width: styles.borderBottomWidth},
{style: styles.borderLeftStyle, color: styles.borderLeftColor, width: styles.borderLeftWidth}
];
const backgroundPaintingArea = calculateBackgroundCurvedPaintingArea(
getBackgroundValueForIndex(styles.backgroundClip, 0),
paint.curves
);
if (hasBackground || styles.boxShadow.length) {
this.ctx.save();
this.path(backgroundPaintingArea);
this.ctx.clip();
if (!isTransparent(styles.backgroundColor)) {
this.ctx.fillStyle = asString(styles.backgroundColor);
this.ctx.fill();
}
await this.renderBackgroundImage(paint.container);
this.ctx.restore();
styles.boxShadow
.slice(0)
.reverse()
.forEach((shadow) => {
this.ctx.save();
const borderBoxArea = calculateBorderBoxPath(paint.curves);
const maskOffset = shadow.inset ? 0 : MASK_OFFSET;
const shadowPaintingArea = transformPath(
borderBoxArea,
-maskOffset + (shadow.inset ? 1 : -1) * shadow.spread.number,
(shadow.inset ? 1 : -1) * shadow.spread.number,
shadow.spread.number * (shadow.inset ? -2 : 2),
shadow.spread.number * (shadow.inset ? -2 : 2)
);
if (shadow.inset) {
this.path(borderBoxArea);
this.ctx.clip();
this.mask(shadowPaintingArea);
} else {
this.mask(borderBoxArea);
this.ctx.clip();
this.path(shadowPaintingArea);
}
this.ctx.shadowOffsetX = shadow.offsetX.number + maskOffset;
this.ctx.shadowOffsetY = shadow.offsetY.number;
this.ctx.shadowColor = asString(shadow.color);
this.ctx.shadowBlur = shadow.blur.number;
this.ctx.fillStyle = shadow.inset ? asString(shadow.color) : 'rgba(0,0,0,1)';
this.ctx.fill();
this.ctx.restore();
});
}
let side = 0;
for (const border of borders) {
if (border.style !== BORDER_STYLE.NONE && !isTransparent(border.color) && border.width > 0) {
if (border.style === BORDER_STYLE.DASHED) {
await this.renderDashedDottedBorder(
border.color,
border.width,
side,
paint.curves,
BORDER_STYLE.DASHED
);
} else if (border.style === BORDER_STYLE.DOTTED) {
await this.renderDashedDottedBorder(
border.color,
border.width,
side,
paint.curves,
BORDER_STYLE.DOTTED
);
} else if (border.style === BORDER_STYLE.DOUBLE) {
await this.renderDoubleBorder(border.color, border.width, side, paint.curves);
} else {
await this.renderSolidBorder(border.color, side, paint.curves);
}
}
side++;
}
}
async renderDashedDottedBorder(
color: Color,
width: number,
side: number,
curvePoints: BoundCurves,
style: BORDER_STYLE
): Promise<void> {
this.ctx.save();
const strokePaths = parsePathForBorderStroke(curvePoints, side);
const boxPaths = parsePathForBorder(curvePoints, side);
if (style === BORDER_STYLE.DASHED) {
this.path(boxPaths);
this.ctx.clip();
}
let startX, startY, endX, endY;
if (isBezierCurve(boxPaths[0])) {
startX = (boxPaths[0] as BezierCurve).start.x;
startY = (boxPaths[0] as BezierCurve).start.y;
} else {
startX = (boxPaths[0] as Vector).x;
startY = (boxPaths[0] as Vector).y;
}
if (isBezierCurve(boxPaths[1])) {
endX = (boxPaths[1] as BezierCurve).end.x;
endY = (boxPaths[1] as BezierCurve).end.y;
} else {
endX = (boxPaths[1] as Vector).x;
endY = (boxPaths[1] as Vector).y;
}
let length;
if (side === 0 || side === 2) {
length = Math.abs(startX - endX);
} else {
length = Math.abs(startY - endY);
}
this.ctx.beginPath();
if (style === BORDER_STYLE.DOTTED) {
this.formatPath(strokePaths);
} else {
this.formatPath(boxPaths.slice(0, 2));
}
let dashLength = width < 3 ? width * 3 : width * 2;
let spaceLength = width < 3 ? width * 2 : width;
if (style === BORDER_STYLE.DOTTED) {
dashLength = width;
spaceLength = width;
}
let useLineDash = true;
if (length <= dashLength * 2) {
useLineDash = false;
} else if (length <= dashLength * 2 + spaceLength) {
const multiplier = length / (2 * dashLength + spaceLength);
dashLength *= multiplier;
spaceLength *= multiplier;
} else {
const numberOfDashes = Math.floor((length + spaceLength) / (dashLength + spaceLength));
const minSpace = (length - numberOfDashes * dashLength) / (numberOfDashes - 1);
const maxSpace = (length - (numberOfDashes + 1) * dashLength) / numberOfDashes;
spaceLength =
maxSpace <= 0 || Math.abs(spaceLength - minSpace) < Math.abs(spaceLength - maxSpace)
? minSpace
: maxSpace;
}
if (useLineDash) {
if (style === BORDER_STYLE.DOTTED) {
this.ctx.setLineDash([0, dashLength + spaceLength]);
} else {
this.ctx.setLineDash([dashLength, spaceLength]);
}
}
if (style === BORDER_STYLE.DOTTED) {
this.ctx.lineCap = 'round';
this.ctx.lineWidth = width;
} else {
this.ctx.lineWidth = width * 2 + 1.1;
}
this.ctx.strokeStyle = asString(color);
this.ctx.stroke();
this.ctx.setLineDash([]);
// dashed round edge gap
if (style === BORDER_STYLE.DASHED) {
if (isBezierCurve(boxPaths[0])) {
const path1 = boxPaths[3] as BezierCurve;
const path2 = boxPaths[0] as BezierCurve;
this.ctx.beginPath();
this.formatPath([new Vector(path1.end.x, path1.end.y), new Vector(path2.start.x, path2.start.y)]);
this.ctx.stroke();
}
if (isBezierCurve(boxPaths[1])) {
const path1 = boxPaths[1] as BezierCurve;
const path2 = boxPaths[2] as BezierCurve;
this.ctx.beginPath();
this.formatPath([new Vector(path1.end.x, path1.end.y), new Vector(path2.start.x, path2.start.y)]);
this.ctx.stroke();
}
}
this.ctx.restore();
}
async render(element: ElementContainer): Promise<HTMLCanvasElement> {
if (this.options.backgroundColor) {
this.ctx.fillStyle = asString(this.options.backgroundColor);
this.ctx.fillRect(
this.options.x - this.options.scrollX,
this.options.y - this.options.scrollY,
this.options.width,
this.options.height
);
}
const stack = parseStackingContexts(element);
await this.renderStack(stack);
this.applyEffects([], EffectTarget.BACKGROUND_BORDERS);
return this.canvas;
}
}
const isTextInputElement = (
container: ElementContainer
): container is InputElementContainer | TextareaElementContainer | SelectElementContainer => {
if (container instanceof TextareaElementContainer) {
return true;
} else if (container instanceof SelectElementContainer) {
return true;
} else if (container instanceof InputElementContainer && container.type !== RADIO && container.type !== CHECKBOX) {
return true;
}
return false;
};
const calculateBackgroundCurvedPaintingArea = (clip: BACKGROUND_CLIP, curves: BoundCurves): Path[] => {
switch (clip) {
case BACKGROUND_CLIP.BORDER_BOX:
return calculateBorderBoxPath(curves);
case BACKGROUND_CLIP.CONTENT_BOX:
return calculateContentBoxPath(curves);
case BACKGROUND_CLIP.PADDING_BOX:
default:
return calculatePaddingBoxPath(curves);
}
};
const canvasTextAlign = (textAlign: TEXT_ALIGN): CanvasTextAlign => {
switch (textAlign) {
case TEXT_ALIGN.CENTER:
return 'center';
case TEXT_ALIGN.RIGHT:
return 'right';
case TEXT_ALIGN.LEFT:
default:
return 'left';
}
};