[canviz] r494 committed - support strikethrough for canvas text

[can...@googlecode.com]

Revision: 494
Author: ryandesign.com
Date: Tue Sep 17 23:13:46 2013 UTC
Log: support strikethrough for canvas text

http://code.google.com/p/canviz/source/detail?r=494

Modified:
/canviz/trunk/src/Entity.js

=======================================
--- /canviz/trunk/src/Entity.js Tue Sep 17 18:55:42 2013 UTC
+++ /canviz/trunk/src/Entity.js Tue Sep 17 23:13:46 2013 UTC
@@ -191,17 +191,21 @@
// xdot uses pen color for text, but canvas uses fill
color
ctx.fillStyle = ctx.strokeStyle;
ctx.fillText(str, 0, 0);
- if (textStyle & TEXT_UNDERLINE) {
- var emHeightAscent = metrics.emHeightAscent ||
fontSize;
+ if (textStyle & TEXT_STRIKETHROUGH || textStyle &
TEXT_UNDERLINE) {
+ var emHeightAscent = metrics.emHeightAscent ||
fontSize; // wild approximation
var emHeightDescent = metrics.emHeightDescent ||
fontSize / 4; // wild approximation
var emHeight = emHeightAscent + emHeightDescent;
- var underlinePosition = emHeightDescent / 2; // wild
approximation
+ var linePositions = [];
+ if (textStyle & TEXT_STRIKETHROUGH)
linePositions.push(-emHeightAscent / 3.5); // wild approximation
+ if (textStyle & TEXT_UNDERLINE)
linePositions.push(emHeightDescent / 2); // wild approximation
ctx.lineWidth = emHeight / 18; // wild approximation
ctx.lineCap = 'butt';
- ctx.beginPath();
- ctx.moveTo(0, underlinePosition);
- ctx.lineTo(textWidth, underlinePosition);
- ctx.stroke();
+ for (i = 0; i < linePositions.length; ++i) {
+ ctx.beginPath();
+ ctx.moveTo(0, linePositions[i]);
+ ctx.lineTo(textWidth, linePositions[i]);
+ ctx.stroke();
+ }
}

if (0) {
@@ -383,6 +387,7 @@
} else {
y0 -= this.canviz.height;
y1 -= this.canviz.height;
+ // use r1 as a temporary variable to avoid creating another var
r1 = y1;
y1 = y0;
y0 = r1;