Created
April 14, 2010 16:59
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draw a multiline string in a html5 canvas element including rotation font fontsize and color
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| /* | |
| * draw a multiline string rotated in a canvas | |
| * | |
| * @param ctx (M) context of the canvas | |
| * @param text (M) string may contain \n | |
| * @param posX (M) horizontal start position | |
| * @param posY (M) vertical start position | |
| * @param textColor color | |
| * @param rotation in degrees (by 360) | |
| * @param font must be installed on client use websafe | |
| * @param fonSize in Pixels | |
| * | |
| * all (M) params are mandatory - rest is optional | |
| */ | |
| function drawString(ctx, text, posX, posY, textColor, rotation, font, fontSize) { | |
| var lines = text.split("\n"); | |
| if (!rotation) rotation = 0; | |
| if (!font) font = "'serif'"; | |
| if (!fontSize) fontSize = 16; | |
| if (!textColor) textColor = '#000000'; | |
| ctx.save(); | |
| ctx.font = fontSize + "px " + font; | |
| ctx.fillStyle = textColor; | |
| ctx.translate(posX, posY); | |
| ctx.rotate(rotation * Math.PI / 180); | |
| for (i = 0; i < lines.length; i++) { | |
| ctx.fillText(lines[i],0, i*fontSize); | |
| } | |
| ctx.restore(); | |
| } | |
| /* end */ |
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| <html> | |
| <head> | |
| <title>test</title> | |
| <script type="text/javascript"> | |
| /* | |
| * draw a multiline string rotated in a canvas | |
| * | |
| * @param ctx (M) context of the canvas | |
| * @param text (M) string may contain \n | |
| * @param posX (M) horizontal start position | |
| * @param posY (M) vertical start position | |
| * @param textColor color | |
| * @param rotation in degrees (by 360) | |
| * @param font must be installed on client use websafe | |
| * @param fonSize in Pixels | |
| * | |
| * all (M) params are mandatory - rest is optional | |
| */ | |
| function drawString(ctx, text, posX, posY, textColor, rotation, font, fontSize) { | |
| var lines = text.split("\n"); | |
| if (!rotation) rotation = 0; | |
| if (!font) font = "'serif'"; | |
| if (!fontSize) fontSize = 16; | |
| if (!textColor) textColor = '#000000'; | |
| ctx.save(); | |
| ctx.font = fontSize + "px " + font; | |
| ctx.fillStyle = textColor; | |
| ctx.translate(posX, posY); | |
| ctx.rotate(rotation * Math.PI / 180); | |
| for (i = 0; i < lines.length; i++) { | |
| ctx.fillText(lines[i],0, i*fontSize); | |
| } | |
| ctx.restore(); | |
| } | |
| function run() { | |
| var nbc = document.getElementById("nb").getContext('2d'); | |
| drawString(nbc, 'hallo wie gehts?\ndas ist ein Winkel von 30 Grad!', 200, 200, '#444',30,"Chalkduster",36); | |
| drawString(nbc, 'auf\'m Kopf', 500, 100, '#363',180,"Chalkduster",24); | |
| drawString(nbc, 'und alles mit HTML5 JS coool',500,300,'#a66',-30,"Trebuchet MS",24); | |
| drawString(nbc, 'nach unten',10,10,'#66a',90,"Trebuchet MS",24); | |
| drawString(nbc, 'nach oben',27,590,'#66a',-90,"sans-serif",24); | |
| } | |
| </script> | |
| </head> | |
| <body onload="run();"> | |
| <canvas id="nb" width="800" height="600"></canvas> | |
| </body> | |
| </html> |
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Very Useful code. I've been working on this since last 4 days But couldn't find proper answer You saved my day's and money. Thanks.