skia2/tools/colorspaceinfo.cpp

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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Resources.h"
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkCodec.h"
#include "SkColorSpace_A2B.h"
#include "SkColorSpace_XYZ.h"
#include "SkColorSpacePriv.h"
#include "SkCommandLineFlags.h"
#include "SkImageEncoder.h"
#include "SkMatrix44.h"
#include "SkOSFile.h"
#include "sk_tool_utils.h"
DEFINE_string(input, "input.png", "A path to the input image or icc profile.");
DEFINE_string(gamut_output, "gamut_output.png", "A path to the output gamut image.");
DEFINE_string(gamma_output, "gamma_output.png", "A path to the output gamma image.");
DEFINE_bool(sRGB_gamut, false, "Draws the sRGB gamut on the gamut visualization.");
DEFINE_bool(adobeRGB, false, "Draws the Adobe RGB gamut on the gamut visualization.");
DEFINE_bool(sRGB_gamma, false, "Draws the sRGB gamma on all gamma output images.");
DEFINE_string(uncorrected, "", "A path to reencode the uncorrected input image.");
static const char* kRGBChannelNames[3] = {
"Red ", "Green", "Blue "
};
static const SkColor kRGBChannelColors[3] = {
SkColorSetARGB(164, 255, 32, 32),
SkColorSetARGB(164, 32, 255, 32),
SkColorSetARGB(164, 32, 32, 255)
};
static void dump_transfer_fn(SkGammaNamed gammaNamed) {
switch (gammaNamed) {
case kSRGB_SkGammaNamed:
SkDebugf("Transfer Function: sRGB\n");
return;
case k2Dot2Curve_SkGammaNamed:
SkDebugf("Exponential Transfer Function: Exponent 2.2\n");
return;
case kLinear_SkGammaNamed:
SkDebugf("Transfer Function: Linear\n");
return;
default:
break;
}
}
static void dump_transfer_fn(const SkGammas& gammas) {
SkASSERT(gammas.channels() == 3);
for (int i = 0; i < gammas.channels(); i++) {
if (gammas.isNamed(i)) {
switch (gammas.data(i).fNamed) {
case kSRGB_SkGammaNamed:
SkDebugf("%s Transfer Function: sRGB\n", kRGBChannelNames[i]);
return;
case k2Dot2Curve_SkGammaNamed:
SkDebugf("%s Transfer Function: Exponent 2.2\n", kRGBChannelNames[i]);
return;
case kLinear_SkGammaNamed:
SkDebugf("%s Transfer Function: Linear\n", kRGBChannelNames[i]);
return;
default:
SkASSERT(false);
continue;
}
} else if (gammas.isValue(i)) {
SkDebugf("%s Transfer Function: Exponent %.3f\n", kRGBChannelNames[i],
gammas.data(i).fValue);
} else if (gammas.isParametric(i)) {
const SkColorSpaceTransferFn& fn = gammas.data(i).params(&gammas);
SkDebugf("%s Transfer Function: Parametric A = %.3f, B = %.3f, C = %.3f, D = %.3f, "
"E = %.3f, F = %.3f, G = %.3f\n", kRGBChannelNames[i], fn.fA, fn.fB, fn.fC,
fn.fD, fn.fE, fn.fF, fn.fG);
} else {
SkASSERT(gammas.isTable(i));
SkDebugf("%s Transfer Function: Table (%d entries)\n", kRGBChannelNames[i],
gammas.data(i).fTable.fSize);
}
}
}
static inline float parametric(const SkColorSpaceTransferFn& fn, float x) {
return x >= fn.fD ? powf(fn.fA*x + fn.fB, fn.fG) + fn.fE
: fn.fC*x + fn.fF;
}
static void draw_transfer_fn(SkCanvas* canvas, SkGammaNamed gammaNamed, const SkGammas* gammas,
SkColor color, int col) {
SkColorSpaceTransferFn fn[4];
struct TableInfo {
const float* fTable;
int fSize;
};
TableInfo table[4];
bool isTable[4] = {false, false, false, false};
const int channels = gammas ? gammas->channels() : 1;
SkASSERT(channels <= 4);
if (kNonStandard_SkGammaNamed != gammaNamed) {
dump_transfer_fn(gammaNamed);
for (int i = 0; i < channels; ++i) {
named_to_parametric(&fn[i], gammaNamed);
}
} else {
SkASSERT(gammas);
dump_transfer_fn(*gammas);
for (int i = 0; i < channels; ++i) {
if (gammas->isTable(i)) {
table[i].fTable = gammas->table(i);
table[i].fSize = gammas->data(i).fTable.fSize;
isTable[i] = true;
} else {
switch (gammas->type(i)) {
case SkGammas::Type::kNamed_Type:
named_to_parametric(&fn[i], gammas->data(i).fNamed);
break;
case SkGammas::Type::kValue_Type:
value_to_parametric(&fn[i], gammas->data(i).fValue);
break;
case SkGammas::Type::kParam_Type:
fn[i] = gammas->params(i);
break;
default:
SkASSERT(false);
}
}
}
}
SkPaint paint;
paint.setStyle(SkPaint::kStroke_Style);
paint.setColor(color);
paint.setStrokeWidth(2.0f);
// note: gamma has positive values going up in this image so this origin is
// the bottom left and we must subtract y instead of adding.
const float gap = 16.0f;
const float cellWidth = 500.0f;
const float cellHeight = 500.0f;
const float gammaWidth = cellWidth - 2 * gap;
const float gammaHeight = cellHeight - 2 * gap;
// gamma origin point
const float ox = gap + cellWidth * col;
const float oy = gap + gammaHeight;
for (int i = 0; i < channels; ++i) {
if (kNonStandard_SkGammaNamed == gammaNamed) {
paint.setColor(kRGBChannelColors[i]);
} else {
paint.setColor(color);
}
if (isTable[i]) {
auto tx = [&table,i](int index) {
return index / (table[i].fSize - 1.0f);
};
for (int ti = 1; ti < table[i].fSize; ++ti) {
canvas->drawLine(ox + gammaWidth * tx(ti - 1),
oy - gammaHeight * table[i].fTable[ti - 1],
ox + gammaWidth * tx(ti),
oy - gammaHeight * table[i].fTable[ti],
paint);
}
} else {
const float step = 0.01f;
float yPrev = parametric(fn[i], 0.0f);
for (float x = step; x <= 1.0f; x += step) {
const float y = parametric(fn[i], x);
canvas->drawLine(ox + gammaWidth * (x - step), oy - gammaHeight * yPrev,
ox + gammaWidth * x, oy - gammaHeight * y,
paint);
yPrev = y;
}
}
}
paint.setColor(0xFF000000);
paint.setStrokeWidth(3.0f);
canvas->drawRect({ ox, oy - gammaHeight, ox + gammaWidth, oy }, paint);
}
/**
* Loads the triangular gamut as a set of three points.
*/
static void load_gamut(SkPoint rgb[], const SkMatrix44& xyz) {
// rx = rX / (rX + rY + rZ)
// ry = rX / (rX + rY + rZ)
// gx, gy, bx, and gy are calulcated similarly.
float rSum = xyz.get(0, 0) + xyz.get(1, 0) + xyz.get(2, 0);
float gSum = xyz.get(0, 1) + xyz.get(1, 1) + xyz.get(2, 1);
float bSum = xyz.get(0, 2) + xyz.get(1, 2) + xyz.get(2, 2);
rgb[0].fX = xyz.get(0, 0) / rSum;
rgb[0].fY = xyz.get(1, 0) / rSum;
rgb[1].fX = xyz.get(0, 1) / gSum;
rgb[1].fY = xyz.get(1, 1) / gSum;
rgb[2].fX = xyz.get(0, 2) / bSum;
rgb[2].fY = xyz.get(1, 2) / bSum;
}
/**
* Calculates the area of the triangular gamut.
*/
static float calculate_area(SkPoint abc[]) {
SkPoint a = abc[0];
SkPoint b = abc[1];
SkPoint c = abc[2];
return 0.5f * SkTAbs(a.fX*b.fY + b.fX*c.fY - a.fX*c.fY - c.fX*b.fY - b.fX*a.fY);
}
static void draw_gamut(SkCanvas* canvas, const SkMatrix44& xyz, const char* name, SkColor color,
bool label) {
// Report the XYZ values.
SkDebugf("%s\n", name);
SkDebugf(" R G B\n");
SkDebugf("X %.3f %.3f %.3f\n", xyz.get(0, 0), xyz.get(0, 1), xyz.get(0, 2));
SkDebugf("Y %.3f %.3f %.3f\n", xyz.get(1, 0), xyz.get(1, 1), xyz.get(1, 2));
SkDebugf("Z %.3f %.3f %.3f\n", xyz.get(2, 0), xyz.get(2, 1), xyz.get(2, 2));
// Calculate the points in the gamut from the XYZ values.
SkPoint rgb[4];
load_gamut(rgb, xyz);
// Report the area of the gamut.
SkDebugf("Area of Gamut: %.3f\n\n", calculate_area(rgb));
// Magic constants that help us place the gamut triangles in the appropriate position
// on the canvas.
const float xScale = 2071.25f; // Num pixels from 0 to 1 in x
const float xOffset = 241.0f; // Num pixels until start of x-axis
const float yScale = 2067.78f; // Num pixels from 0 to 1 in y
const float yOffset = -144.78f; // Num pixels until start of y-axis
// (negative because y extends beyond image bounds)
// Now transform the points so they can be drawn on our canvas.
// Note that y increases as we move down the canvas.
rgb[0].fX = xOffset + xScale * rgb[0].fX;
rgb[0].fY = yOffset + yScale * (1.0f - rgb[0].fY);
rgb[1].fX = xOffset + xScale * rgb[1].fX;
rgb[1].fY = yOffset + yScale * (1.0f - rgb[1].fY);
rgb[2].fX = xOffset + xScale * rgb[2].fX;
rgb[2].fY = yOffset + yScale * (1.0f - rgb[2].fY);
// Repeat the first point to connect the polygon.
rgb[3] = rgb[0];
SkPaint paint;
paint.setColor(color);
paint.setStrokeWidth(6.0f);
paint.setTextSize(75.0f);
canvas->drawPoints(SkCanvas::kPolygon_PointMode, 4, rgb, paint);
if (label) {
canvas->drawText("R", 1, rgb[0].fX + 5.0f, rgb[0].fY + 75.0f, paint);
canvas->drawText("G", 1, rgb[1].fX + 5.0f, rgb[1].fY - 5.0f, paint);
canvas->drawText("B", 1, rgb[2].fX - 75.0f, rgb[2].fY - 5.0f, paint);
}
}
int main(int argc, char** argv) {
SkCommandLineFlags::SetUsage(
"Usage: colorspaceinfo --input <path to input image or icc profile> "
"--gamma_output <path to output gamma image> "
"--gamut_output <path to output gamut image>"
"--sRGB <draw canonical sRGB gamut> "
"--adobeRGB <draw canonical Adobe RGB gamut> "
"--uncorrected <path to reencoded, uncorrected input image>\n"
"Description: Writes visualizations of the color space to the output image(s) ."
"Also, if a path is provided, writes uncorrected bytes to an unmarked "
"png, for comparison with the input image.\n");
SkCommandLineFlags::Parse(argc, argv);
const char* input = FLAGS_input[0];
const char* gamut_output = FLAGS_gamut_output[0];
const char* gamma_output = FLAGS_gamma_output[0];
if (!input || !gamut_output || !gamma_output) {
SkCommandLineFlags::PrintUsage();
return -1;
}
sk_sp<SkData> data(SkData::MakeFromFileName(input));
if (!data) {
SkDebugf("Cannot find input image.\n");
return -1;
}
std::unique_ptr<SkCodec> codec(SkCodec::NewFromData(data));
sk_sp<SkColorSpace> colorSpace = nullptr;
const bool isImage = (codec != nullptr);
if (isImage) {
colorSpace = sk_ref_sp(codec->getInfo().colorSpace());
} else {
colorSpace = SkColorSpace::MakeICC(data->bytes(), data->size());
}
if (!colorSpace) {
SkDebugf("Cannot create codec or icc profile from input file.\n");
return -1;
}
// Load a graph of the CIE XYZ color gamut.
SkBitmap gamutCanvasBitmap;
if (!GetResourceAsBitmap("gamut.png", &gamutCanvasBitmap)) {
SkDebugf("Program failure.\n");
return -1;
}
SkCanvas gamutCanvas(gamutCanvasBitmap);
SkBitmap gammaCanvasBitmap;
gammaCanvasBitmap.allocN32Pixels(500, 500);
SkCanvas gammaCanvas(gammaCanvasBitmap);
// Draw the sRGB gamut if requested.
if (FLAGS_sRGB_gamut) {
sk_sp<SkColorSpace> sRGBSpace = SkColorSpace::MakeSRGB();
const SkMatrix44* mat = as_CSB(sRGBSpace)->toXYZD50();
SkASSERT(mat);
draw_gamut(&gamutCanvas, *mat, "sRGB", 0xFFFF9394, false);
}
// Draw the Adobe RGB gamut if requested.
if (FLAGS_adobeRGB) {
sk_sp<SkColorSpace> adobeRGBSpace =
SkColorSpace_Base::MakeNamed(SkColorSpace_Base::kAdobeRGB_Named);
const SkMatrix44* mat = as_CSB(adobeRGBSpace)->toXYZD50();
SkASSERT(mat);
draw_gamut(&gamutCanvas, *mat, "Adobe RGB", 0xFF31a9e1, false);
}
int gammaCol = 0;
if (SkColorSpace_Base::Type::kXYZ == as_CSB(colorSpace)->type()) {
const SkMatrix44* mat = as_CSB(colorSpace)->toXYZD50();
SkASSERT(mat);
auto xyz = static_cast<SkColorSpace_XYZ*>(colorSpace.get());
draw_gamut(&gamutCanvas, *mat, input, 0xFF000000, true);
if (FLAGS_sRGB_gamma) {
draw_transfer_fn(&gammaCanvas, kSRGB_SkGammaNamed, nullptr, 0xFFFF9394, gammaCol);
}
draw_transfer_fn(&gammaCanvas, xyz->gammaNamed(), xyz->gammas(), 0xFF000000, gammaCol++);
} else {
SkDebugf("Color space is defined using an A2B tag. It cannot be represented by "
"a transfer function and to D50 matrix.\n");
return -1;
}
// marker to tell the web-tool the names of all images output
SkDebugf("=========\n");
auto saveCanvasBitmap = [](const SkBitmap& bitmap, const char *fname) {
// Finally, encode the result to the output file.
sk_sp<SkData> out = sk_tool_utils::EncodeImageToData(bitmap, SkEncodedImageFormat::kPNG,
100);
if (!out) {
SkDebugf("Failed to encode %s output.\n", fname);
return false;
}
SkFILEWStream stream(fname);
if (!stream.write(out->data(), out->size())) {
SkDebugf("Failed to write %s output.\n", fname);
return false;
}
// record name of canvas
SkDebugf("%s\n", fname);
return true;
};
// only XYZ images have a gamut visualization since the matrix in A2B is not
// a gamut adjustment from RGB->XYZ always (or ever)
if (SkColorSpace_Base::Type::kXYZ == as_CSB(colorSpace)->type() &&
!saveCanvasBitmap(gamutCanvasBitmap, gamut_output)) {
return -1;
}
if (gammaCol > 0 && !saveCanvasBitmap(gammaCanvasBitmap, gamma_output)) {
return -1;
}
if (isImage) {
SkDebugf("%s\n", input);
}
// Also, if requested, decode and reencode the uncorrected input image.
if (!FLAGS_uncorrected.isEmpty() && isImage) {
SkBitmap bitmap;
int width = codec->getInfo().width();
int height = codec->getInfo().height();
bitmap.allocN32Pixels(width, height, kOpaque_SkAlphaType == codec->getInfo().alphaType());
SkImageInfo decodeInfo = SkImageInfo::MakeN32(width, height, kUnpremul_SkAlphaType);
if (SkCodec::kSuccess != codec->getPixels(decodeInfo, bitmap.getPixels(),
bitmap.rowBytes())) {
SkDebugf("Could not decode input image.\n");
return -1;
}
sk_sp<SkData> out = sk_tool_utils::EncodeImageToData(bitmap, SkEncodedImageFormat::kPNG,
100);
if (!out) {
SkDebugf("Failed to encode uncorrected image.\n");
return -1;
}
SkFILEWStream bitmapStream(FLAGS_uncorrected[0]);
if (!bitmapStream.write(out->data(), out->size())) {
SkDebugf("Failed to write uncorrected image output.\n");
return -1;
}
SkDebugf("%s\n", FLAGS_uncorrected[0]);
}
return 0;
}