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Use Uint8ClampedArray, when returning data, and remove manual clamping in src/core/jpg.js (issue 4901)

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This patch removes the `clamp0to255` helper function, as well as manual clamping code in `src/core/jpg.js`.
The adjusted constants in `_convertCmykToRgb` were taken from CMYK to RGB conversion code found in `src/core/colorspace.js`.

*Please note:* There will be some very slight movement in a number of existing test-cases, since `Uint8ClampedArray` appears to use `Math.round` (or equivalent) and the old code used (basically) `Math.floor`.
This commit is contained in:
Jonas Jenwald 2017-08-14 15:42:11 +02:00
parent be36c60e0f
commit d6cd5355f0
1 changed files with 36 additions and 47 deletions
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83
src/core/jpg.js
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@ -600,10 +600,6 @@ var JpegImage = (function JpegImageClosure() {
return component.blockData; return component.blockData;
} }
function clamp0to255(a) {
return a <= 0 ? 0 : a >= 255 ? 255 : a;
}
function findNextFileMarker(data, currentPos, startPos) { function findNextFileMarker(data, currentPos, startPos) {
function peekUint16(pos) { function peekUint16(pos) {
return (data[pos] << 8) | data[pos + 1]; return (data[pos] << 8) | data[pos + 1];
@ -919,7 +915,7 @@ var JpegImage = (function JpegImageClosure() {
var output; var output;
var numComponents = this.components.length; var numComponents = this.components.length;
var dataLength = width * height * numComponents; var dataLength = width * height * numComponents;
var data = new Uint8Array(dataLength); var data = new Uint8ClampedArray(dataLength);
var xScaleBlockOffset = new Uint32Array(width); var xScaleBlockOffset = new Uint32Array(width);
var mask3LSB = 0xfffffff8; // used to clear the 3 LSBs var mask3LSB = 0xfffffff8; // used to clear the 3 LSBs
@ -985,12 +981,12 @@ var JpegImage = (function JpegImageClosure() {
_convertYccToRgb: function convertYccToRgb(data) { _convertYccToRgb: function convertYccToRgb(data) {
var Y, Cb, Cr; var Y, Cb, Cr;
for (var i = 0, length = data.length; i < length; i += 3) { for (var i = 0, length = data.length; i < length; i += 3) {
Y = data[i ]; Y = data[i];
Cb = data[i + 1]; Cb = data[i + 1];
Cr = data[i + 2]; Cr = data[i + 2];
data[i ] = clamp0to255(Y - 179.456 + 1.402 * Cr); data[i] = Y - 179.456 + 1.402 * Cr;
data[i + 1] = clamp0to255(Y + 135.459 - 0.344 * Cb - 0.714 * Cr); data[i + 1] = Y + 135.459 - 0.344 * Cb - 0.714 * Cr;
data[i + 2] = clamp0to255(Y - 226.816 + 1.772 * Cb); data[i + 2] = Y - 226.816 + 1.772 * Cb;
} }
return data; return data;
}, },
@ -999,12 +995,12 @@ var JpegImage = (function JpegImageClosure() {
var Y, Cb, Cr, k; var Y, Cb, Cr, k;
var offset = 0; var offset = 0;
for (var i = 0, length = data.length; i < length; i += 4) { for (var i = 0, length = data.length; i < length; i += 4) {
Y = data[i]; Y = data[i];
Cb = data[i + 1]; Cb = data[i + 1];
Cr = data[i + 2]; Cr = data[i + 2];
k = data[i + 3]; k = data[i + 3];
var r = -122.67195406894 + data[offset++] = -122.67195406894 +
Cb * (-6.60635669420364e-5 * Cb + 0.000437130475926232 * Cr - Cb * (-6.60635669420364e-5 * Cb + 0.000437130475926232 * Cr -
5.4080610064599e-5 * Y + 0.00048449797120281 * k - 5.4080610064599e-5 * Y + 0.00048449797120281 * k -
0.154362151871126) + 0.154362151871126) +
@ -1014,7 +1010,7 @@ var JpegImage = (function JpegImageClosure() {
0.48357088451265) + 0.48357088451265) +
k * (-0.000336197177618394 * k + 0.484791561490776); k * (-0.000336197177618394 * k + 0.484791561490776);
var g = 107.268039397724 + data[offset++] = 107.268039397724 +
Cb * (2.19927104525741e-5 * Cb - 0.000640992018297945 * Cr + Cb * (2.19927104525741e-5 * Cb - 0.000640992018297945 * Cr +
0.000659397001245577 * Y + 0.000426105652938837 * k - 0.000659397001245577 * Y + 0.000426105652938837 * k -
0.176491792462875) + 0.176491792462875) +
@ -1024,7 +1020,7 @@ var JpegImage = (function JpegImageClosure() {
0.25802910206845) + 0.25802910206845) +
k * (-0.000318913117588328 * k - 0.213742400323665); k * (-0.000318913117588328 * k - 0.213742400323665);
var b = -20.810012546947 + data[offset++] = -20.810012546947 +
Cb * (-0.000570115196973677 * Cb - 2.63409051004589e-5 * Cr + Cb * (-0.000570115196973677 * Cb - 2.63409051004589e-5 * Cr +
0.0020741088115012 * Y - 0.00288260236853442 * k + 0.0020741088115012 * Y - 0.00288260236853442 * k +
0.814272968359295) + 0.814272968359295) +
@ -1033,10 +1029,6 @@ var JpegImage = (function JpegImageClosure() {
Y * (0.00174418132927582 * Y - 0.00255243321439347 * k + Y * (0.00174418132927582 * Y - 0.00255243321439347 * k +
0.116935020465145) + 0.116935020465145) +
k * (-0.000343531996510555 * k + 0.24165260232407); k * (-0.000343531996510555 * k + 0.24165260232407);
data[offset++] = clamp0to255(r);
data[offset++] = clamp0to255(g);
data[offset++] = clamp0to255(b);
} }
return data; return data;
}, },
@ -1044,12 +1036,12 @@ var JpegImage = (function JpegImageClosure() {
_convertYcckToCmyk: function convertYcckToCmyk(data) { _convertYcckToCmyk: function convertYcckToCmyk(data) {
var Y, Cb, Cr; var Y, Cb, Cr;
for (var i = 0, length = data.length; i < length; i += 4) { for (var i = 0, length = data.length; i < length; i += 4) {
Y = data[i]; Y = data[i];
Cb = data[i + 1]; Cb = data[i + 1];
Cr = data[i + 2]; Cr = data[i + 2];
data[i ] = clamp0to255(434.456 - Y - 1.402 * Cr); data[i] = 434.456 - Y - 1.402 * Cr;
data[i + 1] = clamp0to255(119.541 - Y + 0.344 * Cb + 0.714 * Cr); data[i + 1] = 119.541 - Y + 0.344 * Cb + 0.714 * Cr;
data[i + 2] = clamp0to255(481.816 - Y - 1.772 * Cb); data[i + 2] = 481.816 - Y - 1.772 * Cb;
// K in data[i + 3] is unchanged // K in data[i + 3] is unchanged
} }
return data; return data;
@ -1058,45 +1050,42 @@ var JpegImage = (function JpegImageClosure() {
_convertCmykToRgb: function convertCmykToRgb(data) { _convertCmykToRgb: function convertCmykToRgb(data) {
var c, m, y, k; var c, m, y, k;
var offset = 0; var offset = 0;
var min = -255 * 255 * 255; var scale = 1 / 255;
var scale = 1 / 255 / 255;
for (var i = 0, length = data.length; i < length; i += 4) { for (var i = 0, length = data.length; i < length; i += 4) {
c = data[i]; c = data[i] * scale;
m = data[i + 1]; m = data[i + 1] * scale;
y = data[i + 2]; y = data[i + 2] * scale;
k = data[i + 3]; k = data[i + 3] * scale;
var r = data[offset++] = 255 +
c * (-4.387332384609988 * c + 54.48615194189176 * m + c * (-4.387332384609988 * c + 54.48615194189176 * m +
18.82290502165302 * y + 212.25662451639585 * k - 18.82290502165302 * y + 212.25662451639585 * k -
72734.4411664936) + 285.2331026137004) +
m * (1.7149763477362134 * m - 5.6096736904047315 * y - m * (1.7149763477362134 * m - 5.6096736904047315 * y -
17.873870861415444 * k - 1401.7366389350734) + 17.873870861415444 * k - 5.497006427196366) +
y * (-2.5217340131683033 * y - 21.248923337353073 * k + y * (-2.5217340131683033 * y - 21.248923337353073 * k +
4465.541406466231) - 17.5119270841813) -
k * (21.86122147463605 * k + 48317.86113160301); k * (21.86122147463605 * k + 189.48180835922747);
var g =
data[offset++] = 255 +
c * (8.841041422036149 * c + 60.118027045597366 * m + c * (8.841041422036149 * c + 60.118027045597366 * m +
6.871425592049007 * y + 31.159100130055922 * k - 6.871425592049007 * y + 31.159100130055922 * k -
20220.756542821975) + 79.2970844816548) +
m * (-15.310361306967817 * m + 17.575251261109482 * y + m * (-15.310361306967817 * m + 17.575251261109482 * y +
131.35250912493976 * k - 48691.05921601825) + 131.35250912493976 * k - 190.9453302588951) +
y * (4.444339102852739 * y + 9.8632861493405 * k - y * (4.444339102852739 * y + 9.8632861493405 * k -
6341.191035517494) - 24.86741582555878) -
k * (20.737325471181034 * k + 47890.15695978492); k * (20.737325471181034 * k + 187.80453709719578);
var b =
data[offset++] = 255 +
c * (0.8842522430003296 * c + 8.078677503112928 * m + c * (0.8842522430003296 * c + 8.078677503112928 * m +
30.89978309703729 * y - 0.23883238689178934 * k - 30.89978309703729 * y - 0.23883238689178934 * k -
3616.812083916688) + 14.183576799673286) +
m * (10.49593273432072 * m + 63.02378494754052 * y + m * (10.49593273432072 * m + 63.02378494754052 * y +
50.606957656360734 * k - 28620.90484698408) + 50.606957656360734 * k - 112.23884253719248) +
y * (0.03296041114873217 * y + 115.60384449646641 * k - y * (0.03296041114873217 * y + 115.60384449646641 * k -
49363.43385999684) - 193.58209356861505) -
k * (22.33816807309886 * k + 45932.16563550634); k * (22.33816807309886 * k + 180.12613974708367);
data[offset++] = r >= 0 ? 255 : r <= min ? 0 : 255 + r * scale | 0;
data[offset++] = g >= 0 ? 255 : g <= min ? 0 : 255 + g * scale | 0;
data[offset++] = b >= 0 ? 255 : b <= min ? 0 : 255 + b * scale | 0;
} }
return data; return data;
}, },
@ -1110,7 +1099,7 @@ var JpegImage = (function JpegImageClosure() {
if (this.numComponents === 1 && forceRGBoutput) { if (this.numComponents === 1 && forceRGBoutput) {
var dataLength = data.length; var dataLength = data.length;
var rgbData = new Uint8Array(dataLength * 3); var rgbData = new Uint8ClampedArray(dataLength * 3);
var offset = 0; var offset = 0;
for (var i = 0; i < dataLength; i++) { for (var i = 0; i < dataLength; i++) {
var grayColor = data[i]; var grayColor = data[i];