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test: try adjusting pixelmatch with signed byte
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@Danielku15
Danielku15 committed Aug 12, 2024
1 parent c456dd2 commit 17e90b4
Showing 1 changed file with 43 additions and 78 deletions.
121 changes: 43 additions & 78 deletions test/java/src/main/java/alphaTab/alphaSkia/test/PixelMatch.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,37 +20,31 @@

final class PixelMatch {
// blend semi-transparent color with white
private static byte blend(byte c, byte a)
{
return (byte)(255 + (c - 255) * a);
private static byte blend(byte c, byte a) {
return (byte) (255 + ((c & 0xFF) - 255) * (a & 0xFF));
}

private static double rgb2Y(byte r, byte g, byte b)
{
return r * 0.29889531 + g * 0.58662247 + b * 0.11448223;
private static double rgb2Y(byte r, byte g, byte b) {
return (r & 0xFF) * 0.29889531 + (g & 0xFF) * 0.58662247 + (b & 0xFF) * 0.11448223;
}

private static double rgb2I(byte r, byte g, byte b)
{
return r * 0.59597799 - g * 0.2741761 - b * 0.32180189;
private static double rgb2I(byte r, byte g, byte b) {
return (r & 0xFF) * 0.59597799 - (g & 0xFF) * 0.2741761 - (b & 0xFF) * 0.32180189;
}

private static double rgb2Q(byte r, byte g, byte b)
{
return r * 0.21147017 - g * 0.52261711 + b * 0.31114694;
private static double rgb2Q(byte r, byte g, byte b) {
return (r & 0xFF) * 0.21147017 - (g & 0xFF) * 0.52261711 + (b & 0xFF) * 0.31114694;
}

private static void drawPixel(byte[] output, int pos, PixelMatchColor color)
{
private static void drawPixel(byte[] output, int pos, PixelMatchColor color) {
//noinspection PointlessArithmeticExpression
output[pos + 0] = color.b();
output[pos + 1] = color.g();
output[pos + 2] = color.r();
output[pos + 3] = (byte)255;
output[pos + 3] = (byte) 255;
}

private static double colorDelta(byte[] img1, byte[] img2, int k, int m, boolean yOnly)
{
private static double colorDelta(byte[] img1, byte[] img2, int k, int m, boolean yOnly) {
//noinspection PointlessArithmeticExpression
var r1 = img1[k + 0];
var g1 = img1[k + 1];
Expand All @@ -66,17 +60,15 @@ private static double colorDelta(byte[] img1, byte[] img2, int k, int m, boolean
if (a1 == a2 && r1 == r2 && g1 == g2 && b1 == b2)
return 0;

if (a1 < (byte)255)
{
a1 /= (byte)255;
if (a1 < (byte) 255) {
a1 /= (byte) 255;
r1 = blend(r1, a1);
g1 = blend(g1, a1);
b1 = blend(b1, a1);
}

if (a2 < (byte)255)
{
a2 /= (byte)255;
if (a2 < (byte) 255) {
a2 /= (byte) 255;
r2 = blend(r2, a2);
g2 = blend(g2, a2);
b2 = blend(b2, a2);
Expand All @@ -94,8 +86,7 @@ private static double colorDelta(byte[] img1, byte[] img2, int k, int m, boolean
}

// check if a pixel has 3+ adjacent pixels of the same color.
private static boolean hasManySiblings(byte[] img, int x1, int y1, int width, int height)
{
private static boolean hasManySiblings(byte[] img, int x1, int y1, int width, int height) {
var distance = 1;
var x0 = Math.max(x1 - distance, 0);
var y0 = Math.max(y1 - distance, 0);
Expand All @@ -105,10 +96,8 @@ private static boolean hasManySiblings(byte[] img, int x1, int y1, int width, in
var zeroes = x1 == x0 || x1 == x2 || y1 == y0 || y1 == y2 ? 1 : 0;

// go through 8 adjacent pixels
for (var x = x0; x <= x2; x++)
{
for (var y = y0; y <= y2; y++)
{
for (var x = x0; x <= x2; x++) {
for (var y = y0; y <= y2; y++) {
if (x == x1 && y == y1)
continue;

Expand All @@ -117,8 +106,7 @@ private static boolean hasManySiblings(byte[] img, int x1, int y1, int width, in
img[pos] == img[pos2] &&
img[pos + 1] == img[pos2 + 1] &&
img[pos + 2] == img[pos2 + 2] &&
img[pos + 3] == img[pos2 + 3])
{
img[pos + 3] == img[pos2 + 3]) {
zeroes++;
}

Expand All @@ -133,8 +121,7 @@ private static boolean hasManySiblings(byte[] img, int x1, int y1, int width, in
// check if a pixel is likely a part of anti-aliasing;
// based on "Anti-aliased Pixel and Intensity Slope Detector" paper by V. Vysniauskas, 2009

private static boolean Antialiased(byte[] img, int x1, int y1, int width, int height, byte[] img2)
{
private static boolean antialiased(byte[] img, int x1, int y1, int width, int height, byte[] img2) {
var distance = 1;
var x0 = Math.max(x1 - distance, 0);
var y0 = Math.max(y1 - distance, 0);
Expand All @@ -150,38 +137,30 @@ private static boolean Antialiased(byte[] img, int x1, int y1, int width, int he
var maxY = 0;

// go through 8 adjacent pixels
for (var x = x0; x <= x2; x++)
{
for (var y = y0; y <= y2; y++)
{
if (x == x1 && y == y1)
{
for (var x = x0; x <= x2; x++) {
for (var y = y0; y <= y2; y++) {
if (x == x1 && y == y1) {
continue;
}

// brightness delta between the center pixel and adjacent one
var delta = colorDelta(img, img, pos, (y * width + x) * 4, true);

// count the number of equal, darker and brighter adjacent pixels
if (delta == 0)
{
if (delta == 0) {
zeroes++;
// if found more than 2 equal siblings, it's definitely not anti-aliasing
if (zeroes > 2)
return false;

// remember the darkest pixel
}
else if (delta < min)
{
} else if (delta < min) {
min = delta;
minX = x;
minY = y;

// remember the brightest pixel
}
else if (delta > max)
{
} else if (delta > max) {
max = delta;
maxX = x;
maxY = y;
Expand All @@ -190,8 +169,7 @@ else if (delta > max)
}

// if there are no both darker and brighter pixels among siblings, it's not anti-aliasing
if (min == 0 || max == 0)
{
if (min == 0 || max == 0) {
return false;
}

Expand All @@ -205,15 +183,12 @@ else if (delta > max)
}

public static PixelMatchResult match(byte[] img1, byte[] img2, byte[] diffPixels, int width, int height,
PixelMatchOptions options)
{
if (img1.length != img2.length || diffPixels.length != img1.length)
{
PixelMatchOptions options) {
if (img1.length != img2.length || diffPixels.length != img1.length) {
throw new IllegalStateException("Image sizes do not match");
}

if (img1.length != width * height * 4)
{
if (img1.length != width * height * 4) {
throw new IllegalStateException("Image data size does not match width/height.");
}

Expand All @@ -222,8 +197,7 @@ public static PixelMatchResult match(byte[] img1, byte[] img2, byte[] diffPixels
var identical = true;
var transparentPixels = 0;

for (var i = 0; i < len; i++)
{
for (var i = 0; i < len; i++) {
//noinspection PointlessArithmeticExpression
var img1R = img1[(i * 4) + 0];
var img1G = img1[(i * 4) + 1];
Expand All @@ -236,20 +210,17 @@ public static PixelMatchResult match(byte[] img1, byte[] img2, byte[] diffPixels
var img2B = img2[(i * 4) + 2];
var img2A = img2[(i * 4) + 3];

if (img1R != img2R || img1G != img2G || img1B != img2B || img1A != img2A)
{
if (img1R != img2R || img1G != img2G || img1B != img2B || img1A != img2A) {
identical = false;
break;
}

if (img1A == 0)
{
if (img1A == 0) {
transparentPixels++;
}
}

if (identical)
{
if (identical) {
return new PixelMatchResult(len, 0, transparentPixels);
}

Expand All @@ -262,32 +233,25 @@ public static PixelMatchResult match(byte[] img1, byte[] img2, byte[] diffPixels
var diff = 0;

// compare each pixel of one image against the other one
for (var y = 0; y < height; y++)
{
for (var x = 0; x < width; x++)
{
for (var y = 0; y < height; y++) {
for (var x = 0; x < width; x++) {
var pos = (y * width + x) * 4;

if (img1[pos + 3] == 0)
{
if (img1[pos + 3] == 0) {
transparentPixels++;
}

// squared YUV distance between colors at this pixel position
var delta = colorDelta(img1, img2, pos, pos, false);

// the color difference is above the threshold
if (delta > maxDelta)
{
if (delta > maxDelta) {
// check it's a real rendering difference or just anti-aliasing
//noinspection StatementWithEmptyBody
if ((Antialiased(img1, x, y, width, height, img2) ||
Antialiased(img2, x, y, width, height, img1)))
{
if ((antialiased(img1, x, y, width, height, img2) ||
antialiased(img2, x, y, width, height, img1))) {
// match
}
else
{
} else {
// found substantial difference not caused by anti-aliasing; draw it as red
drawPixel(diffPixels, pos, options.diffColor());
diff++;
Expand All @@ -300,7 +264,8 @@ public static PixelMatchResult match(byte[] img1, byte[] img2, byte[] diffPixels
return new PixelMatchResult(len, diff, transparentPixels);
}

private PixelMatch() { }
private PixelMatch() {
}
}


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