152 lines
3.2 KiB
JavaScript
Executable file
152 lines
3.2 KiB
JavaScript
Executable file
ig.module(
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'impact.font'
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)
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.requires(
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'impact.image'
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)
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.defines(function(){ "use strict";
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ig.Font = ig.Image.extend({
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widthMap: [],
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indices: [],
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firstChar: 32,
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alpha: 1,
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letterSpacing: 1,
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lineSpacing: 0,
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onload: function( ev ) {
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this._loadMetrics( this.data );
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this.parent( ev );
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},
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widthForString: function( text ) {
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// Multiline?
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if( text.indexOf('\n') !== -1 ) {
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var lines = text.split( '\n' );
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var width = 0;
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for( var i = 0; i < lines.length; i++ ) {
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width = Math.max( width, this._widthForLine(lines[i]) );
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}
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return width;
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}
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else {
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return this._widthForLine( text );
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}
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},
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_widthForLine: function( text ) {
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var width = 0;
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for( var i = 0; i < text.length; i++ ) {
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width += this.widthMap[text.charCodeAt(i) - this.firstChar] + this.letterSpacing;
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}
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return width;
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},
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heightForString: function( text ) {
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return text.split('\n').length * (this.height + this.lineSpacing);
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},
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draw: function( text, x, y, align ) {
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if( typeof(text) != 'string' ) {
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text = text.toString();
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}
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// Multiline?
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if( text.indexOf('\n') !== -1 ) {
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var lines = text.split( '\n' );
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var lineHeight = this.height + this.lineSpacing;
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for( var i = 0; i < lines.length; i++ ) {
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this.draw( lines[i], x, y + i * lineHeight, align );
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}
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return;
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}
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if( align == ig.Font.ALIGN.RIGHT || align == ig.Font.ALIGN.CENTER ) {
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var width = this._widthForLine( text );
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x -= align == ig.Font.ALIGN.CENTER ? width/2 : width;
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}
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if( this.alpha !== 1 ) {
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ig.system.context.globalAlpha = this.alpha;
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}
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for( var i = 0; i < text.length; i++ ) {
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var c = text.charCodeAt(i);
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x += this._drawChar( c - this.firstChar, x, y );
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}
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if( this.alpha !== 1 ) {
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ig.system.context.globalAlpha = 1;
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}
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ig.Image.drawCount += text.length;
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},
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_drawChar: function( c, targetX, targetY ) {
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if( !this.loaded || c < 0 || c >= this.indices.length ) { return 0; }
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var scale = ig.system.scale;
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var charX = this.indices[c] * scale;
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var charY = 0;
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var charWidth = this.widthMap[c] * scale;
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var charHeight = (this.height-2) * scale;
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ig.system.context.drawImage(
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this.data,
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charX, charY,
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charWidth, charHeight,
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ig.system.getDrawPos(targetX), ig.system.getDrawPos(targetY),
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charWidth, charHeight
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);
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return this.widthMap[c] + this.letterSpacing;
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},
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_loadMetrics: function( image ) {
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// Draw the bottommost line of this font image into an offscreen canvas
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// and analyze it pixel by pixel.
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// A run of non-transparent pixels represents a character and its width
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this.height = image.height-1;
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this.widthMap = [];
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this.indices = [];
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var px = ig.getImagePixels( image, 0, image.height-1, image.width, 1 );
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var currentChar = 0;
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var currentWidth = 0;
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for( var x = 0; x < image.width; x++ ) {
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var index = x * 4 + 3; // alpha component of this pixel
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if( px.data[index] > 127 ) {
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currentWidth++;
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}
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else if( px.data[index] < 128 && currentWidth ) {
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this.widthMap.push( currentWidth );
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this.indices.push( x-currentWidth );
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currentChar++;
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currentWidth = 0;
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}
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}
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this.widthMap.push( currentWidth );
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this.indices.push( x-currentWidth );
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}
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});
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ig.Font.ALIGN = {
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LEFT: 0,
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RIGHT: 1,
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CENTER: 2
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};
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});
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