/* eslint max-depth: [2, 8] */
import { Sprite } from '@pixi/sprite';
import { Texture, settings, Rectangle, utils } from '@pixi/core';
import { TEXT_GRADIENT } from './const';
import { TextStyle } from './TextStyle';
import { TextMetrics } from './TextMetrics';
import type { IDestroyOptions } from '@pixi/display';
import type { Renderer } from '@pixi/core';
import type { ITextStyle } from './TextStyle';
const defaultDestroyOptions: IDestroyOptions = {
texture: true,
children: false,
baseTexture: true,
};
interface ModernContext2D extends CanvasRenderingContext2D
{
// for chrome less 94
textLetterSpacing?: number;
// for chrome greater 94
letterSpacing?: number;
}
/**
* A Text Object will create a line or multiple lines of text.
*
* The text is created using the [Canvas API](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API).
*
* The primary advantage of this class over BitmapText is that you have great control over the style of the text,
* which you can change at runtime.
*
* The primary disadvantages is that each piece of text has it's own texture, which can use more memory.
* When text changes, this texture has to be re-generated and re-uploaded to the GPU, taking up time.
*
* To split a line you can use '\n' in your text string, or, on the `style` object,
* change its `wordWrap` property to true and and give the `wordWrapWidth` property a value.
*
* A Text can be created directly from a string and a style object,
* which can be generated [here](https://pixijs.io/pixi-text-style).
*
* ```js
* let text = new PIXI.Text('This is a PixiJS text',{fontFamily : 'Arial', fontSize: 24, fill : 0xff1010, align : 'center'});
* ```
* @memberof PIXI
*/
export class Text extends Sprite
{
/**
* New rendering behavior for letter-spacing which uses Chrome's new native API. This will
* lead to more accurate letter-spacing results because it does not try to manually draw
* each character. However, this Chrome API is experimental and may not serve all cases yet.
*/
public static experimentalLetterSpacing = false;
/** The canvas element that everything is drawn to. */
public canvas: HTMLCanvasElement;
/** The canvas 2d context that everything is drawn with. */
public context: ModernContext2D;
public localStyleID: number;
public dirty: boolean;
/**
* The resolution / device pixel ratio of the canvas.
*
* This is set to automatically match the renderer resolution by default, but can be overridden by setting manually.
* @default PIXI.settings.RESOLUTION
*/
_resolution: number;
_autoResolution: boolean;
/**
* Private tracker for the current text.
* @private
*/
protected _text: string;
/**
* Private tracker for the current font.
* @private
*/
protected _font: string;
/**
* Private tracker for the current style.
* @private
*/
protected _style: TextStyle;
/**
* Private listener to track style changes.
* @private
*/
protected _styleListener: () => void;
/**
* Keep track if this Text object created it's own canvas
* element (`true`) or uses the constructor argument (`false`).
* Used to workaround a GC issues with Safari < 13 when
* destroying Text. See `destroy` for more info.
*/
private _ownCanvas: boolean;
/**
* @param text - The string that you would like the text to display
* @param {object|PIXI.TextStyle} [style] - The style parameters
* @param canvas - The canvas element for drawing text
*/
constructor(text?: string | number, style?: Partial<ITextStyle> | TextStyle, canvas?: HTMLCanvasElement)
{
let ownCanvas = false;
if (!canvas)
{
canvas = settings.ADAPTER.createCanvas();
ownCanvas = true;
}
canvas.width = 3;
canvas.height = 3;
const texture = Texture.from(canvas);
texture.orig = new Rectangle();
texture.trim = new Rectangle();
super(texture);
this._ownCanvas = ownCanvas;
this.canvas = canvas;
this.context = canvas.getContext('2d') as CanvasRenderingContext2D;
this._resolution = settings.RESOLUTION;
this._autoResolution = true;
this._text = null;
this._style = null;
this._styleListener = null;
this._font = '';
this.text = text;
this.style = style;
this.localStyleID = -1;
}
/**
* Renders text to its canvas, and updates its texture.
*
* By default this is used internally to ensure the texture is correct before rendering,
* but it can be used called externally, for example from this class to 'pre-generate' the texture from a piece of text,
* and then shared across multiple Sprites.
* @param respectDirty - Whether to abort updating the text if the Text isn't dirty and the function is called.
*/
public updateText(respectDirty: boolean): void
{
const style = this._style;
// check if style has changed..
if (this.localStyleID !== style.styleID)
{
this.dirty = true;
this.localStyleID = style.styleID;
}
if (!this.dirty && respectDirty)
{
return;
}
this._font = this._style.toFontString();
const context = this.context;
const measured = TextMetrics.measureText(this._text || ' ', this._style, this._style.wordWrap, this.canvas);
const width = measured.width;
const height = measured.height;
const lines = measured.lines;
const lineHeight = measured.lineHeight;
const lineWidths = measured.lineWidths;
const maxLineWidth = measured.maxLineWidth;
const fontProperties = measured.fontProperties;
this.canvas.width = Math.ceil(Math.ceil((Math.max(1, width) + (style.padding * 2))) * this._resolution);
this.canvas.height = Math.ceil(Math.ceil((Math.max(1, height) + (style.padding * 2))) * this._resolution);
context.scale(this._resolution, this._resolution);
context.clearRect(0, 0, this.canvas.width, this.canvas.height);
context.font = this._font;
context.lineWidth = style.strokeThickness;
context.textBaseline = style.textBaseline;
context.lineJoin = style.lineJoin;
context.miterLimit = style.miterLimit;
let linePositionX: number;
let linePositionY: number;
// require 2 passes if a shadow; the first to draw the drop shadow, the second to draw the text
const passesCount = style.dropShadow ? 2 : 1;
// For v4, we drew text at the colours of the drop shadow underneath the normal text. This gave the correct zIndex,
// but features such as alpha and shadowblur did not look right at all, since we were using actual text as a shadow.
//
// For v5.0.0, we moved over to just use the canvas API for drop shadows, which made them look much nicer and more
// visually please, but now because the stroke is drawn and then the fill, drop shadows would appear on both the fill
// and the stroke; and fill drop shadows would appear over the top of the stroke.
//
// For v5.1.1, the new route is to revert to v4 style of drawing text first to get the drop shadows underneath normal
// text, but instead drawing text in the correct location, we'll draw it off screen (-paddingY), and then adjust the
// drop shadow so only that appears on screen (+paddingY). Now we'll have the correct draw order of the shadow
// beneath the text, whilst also having the proper text shadow styling.
for (let i = 0; i < passesCount; ++i)
{
const isShadowPass = style.dropShadow && i === 0;
// we only want the drop shadow, so put text way off-screen
const dsOffsetText = isShadowPass ? Math.ceil(Math.max(1, height) + (style.padding * 2)) : 0;
const dsOffsetShadow = dsOffsetText * this._resolution;
if (isShadowPass)
{
// On Safari, text with gradient and drop shadows together do not position correctly
// if the scale of the canvas is not 1: https://bugs.webkit.org/show_bug.cgi?id=197689
// Therefore we'll set the styles to be a plain black whilst generating this drop shadow
context.fillStyle = 'black';
context.strokeStyle = 'black';
const dropShadowColor = style.dropShadowColor;
const rgb = utils.hex2rgb(typeof dropShadowColor === 'number'
? dropShadowColor
: utils.string2hex(dropShadowColor));
const dropShadowBlur = style.dropShadowBlur * this._resolution;
const dropShadowDistance = style.dropShadowDistance * this._resolution;
context.shadowColor = `rgba(${rgb[0] * 255},${rgb[1] * 255},${rgb[2] * 255},${style.dropShadowAlpha})`;
context.shadowBlur = dropShadowBlur;
context.shadowOffsetX = Math.cos(style.dropShadowAngle) * dropShadowDistance;
context.shadowOffsetY = (Math.sin(style.dropShadowAngle) * dropShadowDistance) + dsOffsetShadow;
}
else
{
// set canvas text styles
context.fillStyle = this._generateFillStyle(style, lines, measured);
// TODO: Can't have different types for getter and setter. The getter shouldn't have the number type as
// the setter converts to string. See this thread for more details:
// https://github.com/microsoft/TypeScript/issues/2521
context.strokeStyle = style.stroke as string;
context.shadowColor = 'black';
context.shadowBlur = 0;
context.shadowOffsetX = 0;
context.shadowOffsetY = 0;
}
let linePositionYShift = (lineHeight - fontProperties.fontSize) / 2;
if (lineHeight - fontProperties.fontSize < 0)
{
linePositionYShift = 0;
}
// draw lines line by line
for (let i = 0; i < lines.length; i++)
{
linePositionX = style.strokeThickness / 2;
linePositionY = ((style.strokeThickness / 2) + (i * lineHeight)) + fontProperties.ascent
+ linePositionYShift;
if (style.align === 'right')
{
linePositionX += maxLineWidth - lineWidths[i];
}
else if (style.align === 'center')
{
linePositionX += (maxLineWidth - lineWidths[i]) / 2;
}
if (style.stroke && style.strokeThickness)
{
this.drawLetterSpacing(
lines[i],
linePositionX + style.padding,
linePositionY + style.padding - dsOffsetText,
true
);
}
if (style.fill)
{
this.drawLetterSpacing(
lines[i],
linePositionX + style.padding,
linePositionY + style.padding - dsOffsetText
);
}
}
}
this.updateTexture();
}
/**
* Render the text with letter-spacing.
* @param text - The text to draw
* @param x - Horizontal position to draw the text
* @param y - Vertical position to draw the text
* @param isStroke - Is this drawing for the outside stroke of the
* text? If not, it's for the inside fill
*/
private drawLetterSpacing(text: string, x: number, y: number, isStroke = false): void
{
const style = this._style;
// letterSpacing of 0 means normal
const letterSpacing = style.letterSpacing;
// Checking that we can use moddern canvas2D api
// https://developer.chrome.com/origintrials/#/view_trial/3585991203293757441
// note: this is unstable API, Chrome less 94 use a `textLetterSpacing`, newest use a letterSpacing
// eslint-disable-next-line max-len
const supportLetterSpacing = Text.experimentalLetterSpacing
&& ('letterSpacing' in CanvasRenderingContext2D.prototype
|| 'textLetterSpacing' in CanvasRenderingContext2D.prototype);
if (letterSpacing === 0 || supportLetterSpacing)
{
if (supportLetterSpacing)
{
this.context.letterSpacing = letterSpacing;
this.context.textLetterSpacing = letterSpacing;
}
if (isStroke)
{
this.context.strokeText(text, x, y);
}
else
{
this.context.fillText(text, x, y);
}
return;
}
let currentPosition = x;
// Using Array.from correctly splits characters whilst keeping emoji together.
// This is not supported on IE as it requires ES6, so regular text splitting occurs.
// This also doesn't account for emoji that are multiple emoji put together to make something else.
// Handling all of this would require a big library itself.
// https://medium.com/@giltayar/iterating-over-emoji-characters-the-es6-way-f06e4589516
// https://github.com/orling/grapheme-splitter
const stringArray = Array.from ? Array.from(text) : text.split('');
let previousWidth = this.context.measureText(text).width;
let currentWidth = 0;
for (let i = 0; i < stringArray.length; ++i)
{
const currentChar = stringArray[i];
if (isStroke)
{
this.context.strokeText(currentChar, currentPosition, y);
}
else
{
this.context.fillText(currentChar, currentPosition, y);
}
let textStr = '';
for (let j = i + 1; j < stringArray.length; ++j)
{
textStr += stringArray[j];
}
currentWidth = this.context.measureText(textStr).width;
currentPosition += previousWidth - currentWidth + letterSpacing;
previousWidth = currentWidth;
}
}
/** Updates texture size based on canvas size. */
private updateTexture(): void
{
const canvas = this.canvas;
if (this._style.trim)
{
const trimmed = utils.trimCanvas(canvas);
if (trimmed.data)
{
canvas.width = trimmed.width;
canvas.height = trimmed.height;
this.context.putImageData(trimmed.data, 0, 0);
}
}
const texture = this._texture;
const style = this._style;
const padding = style.trim ? 0 : style.padding;
const baseTexture = texture.baseTexture;
texture.trim.width = texture._frame.width = canvas.width / this._resolution;
texture.trim.height = texture._frame.height = canvas.height / this._resolution;
texture.trim.x = -padding;
texture.trim.y = -padding;
texture.orig.width = texture._frame.width - (padding * 2);
texture.orig.height = texture._frame.height - (padding * 2);
// call sprite onTextureUpdate to update scale if _width or _height were set
this._onTextureUpdate();
baseTexture.setRealSize(canvas.width, canvas.height, this._resolution);
texture.updateUvs();
this.dirty = false;
}
/**
* Renders the object using the WebGL renderer
* @param renderer - The renderer
*/
protected _render(renderer: Renderer): void
{
if (this._autoResolution && this._resolution !== renderer.resolution)
{
this._resolution = renderer.resolution;
this.dirty = true;
}
this.updateText(true);
super._render(renderer);
}
/** Updates the transform on all children of this container for rendering. */
public updateTransform(): void
{
this.updateText(true);
super.updateTransform();
}
public getBounds(skipUpdate?: boolean, rect?: Rectangle): Rectangle
{
this.updateText(true);
if (this._textureID === -1)
{
// texture was updated: recalculate transforms
skipUpdate = false;
}
return super.getBounds(skipUpdate, rect);
}
/**
* Gets the local bounds of the text object.
* @param rect - The output rectangle.
* @returns The bounds.
*/
public getLocalBounds(rect?: Rectangle): Rectangle
{
this.updateText(true);
return super.getLocalBounds.call(this, rect);
}
/** Calculates the bounds of the Text as a rectangle. The bounds calculation takes the worldTransform into account. */
protected _calculateBounds(): void
{
this.calculateVertices();
// if we have already done this on THIS frame.
this._bounds.addQuad(this.vertexData);
}
/**
* Generates the fill style. Can automatically generate a gradient based on the fill style being an array
* @param style - The style.
* @param lines - The lines of text.
* @param metrics
* @returns The fill style
*/
private _generateFillStyle(
style: TextStyle, lines: string[], metrics: TextMetrics
): string | CanvasGradient | CanvasPattern
{
// TODO: Can't have different types for getter and setter. The getter shouldn't have the number type as
// the setter converts to string. See this thread for more details:
// https://github.com/microsoft/TypeScript/issues/2521
const fillStyle: string | string[] | CanvasGradient | CanvasPattern = style.fill as any;
if (!Array.isArray(fillStyle))
{
return fillStyle;
}
else if (fillStyle.length === 1)
{
return fillStyle[0];
}
// the gradient will be evenly spaced out according to how large the array is.
// ['#FF0000', '#00FF00', '#0000FF'] would created stops at 0.25, 0.5 and 0.75
let gradient: string[] | CanvasGradient;
// a dropshadow will enlarge the canvas and result in the gradient being
// generated with the incorrect dimensions
const dropShadowCorrection = (style.dropShadow) ? style.dropShadowDistance : 0;
// should also take padding into account, padding can offset the gradient
const padding = style.padding || 0;
const width = (this.canvas.width / this._resolution) - dropShadowCorrection - (padding * 2);
const height = (this.canvas.height / this._resolution) - dropShadowCorrection - (padding * 2);
// make a copy of the style settings, so we can manipulate them later
const fill = fillStyle.slice();
const fillGradientStops = style.fillGradientStops.slice();
// wanting to evenly distribute the fills. So an array of 4 colours should give fills of 0.25, 0.5 and 0.75
if (!fillGradientStops.length)
{
const lengthPlus1 = fill.length + 1;
for (let i = 1; i < lengthPlus1; ++i)
{
fillGradientStops.push(i / lengthPlus1);
}
}
// stop the bleeding of the last gradient on the line above to the top gradient of the this line
// by hard defining the first gradient colour at point 0, and last gradient colour at point 1
fill.unshift(fillStyle[0]);
fillGradientStops.unshift(0);
fill.push(fillStyle[fillStyle.length - 1]);
fillGradientStops.push(1);
if (style.fillGradientType === TEXT_GRADIENT.LINEAR_VERTICAL)
{
// start the gradient at the top center of the canvas, and end at the bottom middle of the canvas
gradient = this.context.createLinearGradient(width / 2, padding, width / 2, height + padding);
// we need to repeat the gradient so that each individual line of text has the same vertical gradient effect
// ['#FF0000', '#00FF00', '#0000FF'] over 2 lines would create stops at 0.125, 0.25, 0.375, 0.625, 0.75, 0.875
// Actual height of the text itself, not counting spacing for lineHeight/leading/dropShadow etc
const textHeight = metrics.fontProperties.fontSize + style.strokeThickness;
for (let i = 0; i < lines.length; i++)
{
const lastLineBottom = (metrics.lineHeight * (i - 1)) + textHeight;
const thisLineTop = metrics.lineHeight * i;
let thisLineGradientStart = thisLineTop;
// Handle case where last & this line overlap
if (i > 0 && lastLineBottom > thisLineTop)
{
thisLineGradientStart = (thisLineTop + lastLineBottom) / 2;
}
const thisLineBottom = thisLineTop + textHeight;
const nextLineTop = metrics.lineHeight * (i + 1);
let thisLineGradientEnd = thisLineBottom;
// Handle case where this & next line overlap
if (i + 1 < lines.length && nextLineTop < thisLineBottom)
{
thisLineGradientEnd = (thisLineBottom + nextLineTop) / 2;
}
// textHeight, but as a 0-1 size in global gradient stop space
const gradStopLineHeight = (thisLineGradientEnd - thisLineGradientStart) / height;
for (let j = 0; j < fill.length; j++)
{
// 0-1 stop point for the current line, multiplied to global space afterwards
let lineStop = 0;
if (typeof fillGradientStops[j] === 'number')
{
lineStop = fillGradientStops[j];
}
else
{
lineStop = j / fill.length;
}
let globalStop = Math.min(1, Math.max(0,
(thisLineGradientStart / height) + (lineStop * gradStopLineHeight)));
// There's potential for floating point precision issues at the seams between gradient repeats.
globalStop = Number(globalStop.toFixed(5));
gradient.addColorStop(globalStop, fill[j]);
}
}
}
else
{
// start the gradient at the center left of the canvas, and end at the center right of the canvas
gradient = this.context.createLinearGradient(padding, height / 2, width + padding, height / 2);
// can just evenly space out the gradients in this case, as multiple lines makes no difference
// to an even left to right gradient
const totalIterations = fill.length + 1;
let currentIteration = 1;
for (let i = 0; i < fill.length; i++)
{
let stop: number;
if (typeof fillGradientStops[i] === 'number')
{
stop = fillGradientStops[i];
}
else
{
stop = currentIteration / totalIterations;
}
gradient.addColorStop(stop, fill[i]);
currentIteration++;
}
}
return gradient;
}
/**
* Destroys this text object.
*
* Note* Unlike a Sprite, a Text object will automatically destroy its baseTexture and texture as
* the majority of the time the texture will not be shared with any other Sprites.
* @param options - Options parameter. A boolean will act as if all options
* have been set to that value
* @param {boolean} [options.children=false] - if set to true, all the children will have their
* destroy method called as well. 'options' will be passed on to those calls.
* @param {boolean} [options.texture=true] - Should it destroy the current texture of the sprite as well
* @param {boolean} [options.baseTexture=true] - Should it destroy the base texture of the sprite as well
*/
public destroy(options?: IDestroyOptions | boolean): void
{
if (typeof options === 'boolean')
{
options = { children: options };
}
options = Object.assign({}, defaultDestroyOptions, options);
super.destroy(options);
// set canvas width and height to 0 to workaround memory leak in Safari < 13
// https://stackoverflow.com/questions/52532614/total-canvas-memory-use-exceeds-the-maximum-limit-safari-12
if (this._ownCanvas)
{
this.canvas.height = this.canvas.width = 0;
}
// make sure to reset the context and canvas.. dont want this hanging around in memory!
this.context = null;
this.canvas = null;
this._style = null;
}
/** The width of the Text, setting this will actually modify the scale to achieve the value set. */
get width(): number
{
this.updateText(true);
return Math.abs(this.scale.x) * this._texture.orig.width;
}
set width(value: number)
{
this.updateText(true);
const s = utils.sign(this.scale.x) || 1;
this.scale.x = s * value / this._texture.orig.width;
this._width = value;
}
/** The height of the Text, setting this will actually modify the scale to achieve the value set. */
get height(): number
{
this.updateText(true);
return Math.abs(this.scale.y) * this._texture.orig.height;
}
set height(value: number)
{
this.updateText(true);
const s = utils.sign(this.scale.y) || 1;
this.scale.y = s * value / this._texture.orig.height;
this._height = value;
}
/**
* Set the style of the text.
*
* Set up an event listener to listen for changes on the style object and mark the text as dirty.
*/
get style(): TextStyle | Partial<ITextStyle>
{
// TODO: Can't have different types for getter and setter. The getter shouldn't have the ITextStyle
// since the setter creates the TextStyle. See this thread for more details:
// https://github.com/microsoft/TypeScript/issues/2521
return this._style;
}
set style(style: TextStyle | Partial<ITextStyle>)
{
style = style || {};
if (style instanceof TextStyle)
{
this._style = style;
}
else
{
this._style = new TextStyle(style);
}
this.localStyleID = -1;
this.dirty = true;
}
/** Set the copy for the text object. To split a line you can use '\n'. */
get text(): string
{
return this._text;
}
set text(text: string | number)
{
text = String(text === null || text === undefined ? '' : text);
if (this._text === text)
{
return;
}
this._text = text;
this.dirty = true;
}
/**
* The resolution / device pixel ratio of the canvas.
*
* This is set to automatically match the renderer resolution by default, but can be overridden by setting manually.
* @default 1
*/
get resolution(): number
{
return this._resolution;
}
set resolution(value: number)
{
this._autoResolution = false;
if (this._resolution === value)
{
return;
}
this._resolution = value;
this.dirty = true;
}
}