Sakurai/pdf.js
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Enforce minimum line widths

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This commit is contained in:
Jonas Jenwald 2014-04-11 20:19:39 +02:00
parent a17735d538
commit fc1e2483b4
1 changed files with 26 additions and 9 deletions
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35
src/display/canvas.js
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@ -30,6 +30,9 @@ var MIN_FONT_SIZE = 16;
var MAX_FONT_SIZE = 100; var MAX_FONT_SIZE = 100;
var MAX_GROUP_SIZE = 4096; var MAX_GROUP_SIZE = 4096;
// Heuristic value used when enforcing minimum line widths.
var MIN_WIDTH_FACTOR = 0.65;
var COMPILE_TYPE3_GLYPHS = true; var COMPILE_TYPE3_GLYPHS = true;
var MAX_SIZE_TO_COMPILE = 1000; var MAX_SIZE_TO_COMPILE = 1000;
@ -434,6 +437,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
if (canvasCtx) { if (canvasCtx) {
addContextCurrentTransform(canvasCtx); addContextCurrentTransform(canvasCtx);
} }
this.cachedGetSinglePixelWidth = null;
} }
function putBinaryImageData(ctx, imgData) { function putBinaryImageData(ctx, imgData) {
@ -966,10 +970,14 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
this.current = this.stateStack.pop(); this.current = this.stateStack.pop();
this.ctx.restore(); this.ctx.restore();
this.cachedGetSinglePixelWidth = null;
} }
}, },
transform: function CanvasGraphics_transform(a, b, c, d, e, f) { transform: function CanvasGraphics_transform(a, b, c, d, e, f) {
this.ctx.transform(a, b, c, d, e, f); this.ctx.transform(a, b, c, d, e, f);
this.cachedGetSinglePixelWidth = null;
}, },
// Path // Path
@ -1043,9 +1051,9 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
consumePath = typeof consumePath !== 'undefined' ? consumePath : true; consumePath = typeof consumePath !== 'undefined' ? consumePath : true;
var ctx = this.ctx; var ctx = this.ctx;
var strokeColor = this.current.strokeColor; var strokeColor = this.current.strokeColor;
if (this.current.lineWidth === 0) { // Prevent drawing too thin lines by enforcing a minimum line width.
ctx.lineWidth = this.getSinglePixelWidth(); ctx.lineWidth = Math.max(this.getSinglePixelWidth() * MIN_WIDTH_FACTOR,
} this.current.lineWidth);
// For stroke we want to temporarily change the global alpha to the // For stroke we want to temporarily change the global alpha to the
// stroking alpha. // stroking alpha.
ctx.globalAlpha = this.current.strokeAlpha; ctx.globalAlpha = this.current.strokeAlpha;
@ -1370,7 +1378,13 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
var lineWidth = current.lineWidth; var lineWidth = current.lineWidth;
var scale = current.textMatrixScale; var scale = current.textMatrixScale;
if (scale === 0 || lineWidth === 0) { if (scale === 0 || lineWidth === 0) {
lineWidth = this.getSinglePixelWidth(); var fillStrokeMode = current.textRenderingMode &
TextRenderingMode.FILL_STROKE_MASK;
if (fillStrokeMode === TextRenderingMode.STROKE ||
fillStrokeMode === TextRenderingMode.FILL_STROKE) {
this.cachedGetSinglePixelWidth = null;
lineWidth = this.getSinglePixelWidth() * MIN_WIDTH_FACTOR;
}
} else { } else {
lineWidth /= scale; lineWidth /= scale;
} }
@ -2111,11 +2125,14 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
ctx.beginPath(); ctx.beginPath();
}, },
getSinglePixelWidth: function CanvasGraphics_getSinglePixelWidth(scale) { getSinglePixelWidth: function CanvasGraphics_getSinglePixelWidth(scale) {
var inverse = this.ctx.mozCurrentTransformInverse; if (this.cachedGetSinglePixelWidth === null) {
// max of the current horizontal and vertical scale var inverse = this.ctx.mozCurrentTransformInverse;
return Math.sqrt(Math.max( // max of the current horizontal and vertical scale
(inverse[0] * inverse[0] + inverse[1] * inverse[1]), this.cachedGetSinglePixelWidth = Math.sqrt(Math.max(
(inverse[2] * inverse[2] + inverse[3] * inverse[3]))); (inverse[0] * inverse[0] + inverse[1] * inverse[1]),
(inverse[2] * inverse[2] + inverse[3] * inverse[3])));
}
return this.cachedGetSinglePixelWidth;
}, },
getCanvasPosition: function CanvasGraphics_getCanvasPosition(x, y) { getCanvasPosition: function CanvasGraphics_getCanvasPosition(x, y) {
var transform = this.ctx.mozCurrentTransform; var transform = this.ctx.mozCurrentTransform;