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Sharpen the patterns.

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Draw the patterns with the intended resolution instead of scaling
afterwards. Scaling leads to unclear patterns.

Also:
Make TilingPattern function for paintType switch case.
Make TilingPattern function for bbox clipping.
Make TilingPattern functions for scaling code.
Increase MAX_PATTERN_SIZE to 4096.
Add Singular Value Decomposition function.
This commit is contained in:
Kalervo Kujala 2012-12-27 09:35:25 +02:00
parent d97c5a2b14
commit 6f65fef64b
4 changed files with 230 additions and 43 deletions
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24
src/util.js
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@ -257,6 +257,30 @@ var Util = PDFJS.Util = (function UtilClosure() {
];
};
// This calculation uses Singular Value Decomposition.
// The SVD can be represented with formula A = USV. We are interested in the
// matrix S here because it represents the scale values.
Util.singularValueDecompose2dScale =
function Util_singularValueDecompose2dScale(m) {
var transpose = [m[0], m[2], m[1], m[3]];
// Multiply matrix m with its transpose.
var a = m[0] * transpose[0] + m[1] * transpose[2];
var b = m[0] * transpose[1] + m[1] * transpose[3];
var c = m[2] * transpose[0] + m[3] * transpose[2];
var d = m[2] * transpose[1] + m[3] * transpose[3];
// Solve the second degree polynomial to get roots.
var first = (a + d) / 2;
var second = Math.sqrt((a + d) * (a + d) - 4 * (a * d - c * b)) / 2;
var sx = first + second || 1;
var sy = first - second || 1;
// Scale values are the square roots of the eigenvalues.
return [Math.sqrt(sx), Math.sqrt(sy)];
};
// Normalize rectangle rect=[x1, y1, x2, y2] so that (x1,y1) < (x2,y2)
// For coordinate systems whose origin lies in the bottom-left, this
// means normalization to (BL,TR) ordering. For systems with origin in the