Add interesting features to visualize_color_gamut

tools/visualize_color_gamut.cpp

 /*
  * 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.h"
 #include "SkCommandLineFlags.h"
 #include "SkForceLinking.h"
 #include "SkImageEncoder.h"
 #include "SkMatrix44.h"
 #include "SkOSFile.h"
 
 __SK_FORCE_IMAGE_DECODER_LINKING;
 
-DEFINE_string2(input, i, "input.png", "A path to the input image.");
-DEFINE_string2(output, o, "output.png", "A path to the output image.");
+DEFINE_string(input, "input.png", "A path to the input image.");
+DEFINE_string(output, "output.png", "A path to the output image.");
+DEFINE_bool(sRGB, false, "Draws the sRGB gamut.");
+DEFINE_bool(adobeRGB, false, "Draws the Adobe RGB gamut.");
+DEFINE_string(uncorrected, "", "A path to reencode the uncorrected input image.");
 
 /**
  *  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(0, 1) + xyz.get(0, 2);
     float gSum = xyz.get(1, 0) + xyz.get(1, 1) + xyz.get(1, 2);
     float bSum = xyz.get(2, 0) + xyz.get(2, 1) + xyz.get(2, 2);
     rgb[0].fX = xyz.get(0, 0) / rSum;
     rgb[0].fY = xyz.get(0, 1) / rSum;
     rgb[1].fX = xyz.get(1, 0) / gSum;
     rgb[1].fY = xyz.get(1, 1) / gSum;
     rgb[2].fX = xyz.get(2, 0) / bSum;
     rgb[2].fY = xyz.get(2, 1) / bSum;
 }
 
 /**
  *  Calculates the area of the triangular gamut.
  */
-float calculate_area(SkPoint abc[]) {
+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("          X     Y     Z\n");
+    SkDebugf("Red   %.3f %.3f %.3f\n", xyz.get(0, 0), xyz.get(0, 1), xyz.get(0, 2));
+    SkDebugf("Green %.3f %.3f %.3f\n", xyz.get(1, 0), xyz.get(1, 1), xyz.get(1, 2));
+    SkDebugf("Blue  %.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: visualize_color_gamut --input <path to input image>"
-                                         "--output <path to output image>\n"
-            "Description: Writes a visualization of the color gamut to the output image\n");
+            "Usage: visualize_color_gamut --input <path to input image> "
+                                         "--output <path to output image> "
+                                         "--sRGB <draw canonical sRGB gamut> "
+                                         "--adobeRGB <draw canonical Adobe RGB gamut> "
+                                         "--uncorrected <path to reencoded, uncorrected "
+                                         "               input image>\n"
+            "Description: Writes a visualization of the color gamut to the output image  ."
+                         "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* output = FLAGS_output[0];
     if (!input || !output) {
         SkCommandLineFlags::PrintUsage();
         return -1;
     }
 
     SkAutoTUnref<SkData> data(SkData::NewFromFileName(input));
     if (!data) {
         SkDebugf("Cannot find input image.\n");
         return -1;
     }
     SkAutoTDelete<SkCodec> codec(SkCodec::NewFromData(data));
     if (!codec) {
         SkDebugf("Invalid input image.\n");
         return -1;
     }
 
     // Load a graph of the CIE XYZ color gamut.
-    SkBitmap bitmap;
-    if (!GetResourceAsBitmap("gamut.png", &bitmap)) {
+    SkBitmap gamut;
+    if (!GetResourceAsBitmap("gamut.png", &gamut)) {
         SkDebugf("Program failure.\n");
         return -1;
     }
-    SkCanvas canvas(bitmap);
+    SkCanvas canvas(gamut);
 
+    // Draw the sRGB gamut if requested.
+    if (FLAGS_sRGB) {
+        sk_sp<SkColorSpace> sRGBSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
+        draw_gamut(&canvas, sRGBSpace->xyz(), "sRGB", 0xFFFF9394, false);
+    }
+
+    // Draw the Adobe RGB gamut if requested.
+    if (FLAGS_adobeRGB) {
+        sk_sp<SkColorSpace> adobeRGBSpace = SkColorSpace::NewNamed(SkColorSpace::kAdobeRGB_Named);
+        draw_gamut(&canvas, adobeRGBSpace->xyz(), "Adobe RGB", 0xFF31a9e1, false);
+    }
+
+    // Draw gamut for the input image.
     sk_sp<SkColorSpace> colorSpace = sk_ref_sp(codec->getColorSpace());
     if (!colorSpace) {
         SkDebugf("Image had no embedded color space information.  Defaulting to sRGB.\n");
         colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
     }
+    draw_gamut(&canvas, colorSpace->xyz(), input, 0xFF000000, true);
 
-    // Calculate the points in the gamut from the XYZ values.
-    SkMatrix44 xyz = colorSpace->xyz();
-    SkPoint rgb[4];
-    load_gamut(rgb, xyz);
-
-    // Report the XYZ values.
-    SkDebugf("      X    Y    Z\n");
-    SkDebugf("Red   %.2f %.2f %.2f\n", xyz.get(0, 0), xyz.get(0, 1), xyz.get(0, 2));
-    SkDebugf("Green %.2f %.2f %.2f\n", xyz.get(1, 0), xyz.get(1, 1), xyz.get(1, 2));
-    SkDebugf("Blue  %.2f %.2f %.2f\n", xyz.get(2, 0), xyz.get(2, 1), xyz.get(2, 2));
-
-    // Report the area of the gamut.
-    SkDebugf("Area of Gamut: %g\n", calculate_area(rgb));
-
-    // Now transform the points so they can be drawn on our canvas.  We use 1000 pixels
-    // to represent the space from 0 to 1.  Note that the graph is at an offset of (50, 50).
-    // Also note that y increases as we move down the canvas.
-    rgb[0].fX = 50 + 1000*rgb[0].fX;
-    rgb[0].fY = 50 + 1000*(1 - rgb[0].fY);
-    rgb[1].fX = 50 + 1000*rgb[1].fX;
-    rgb[1].fY = 50 + 1000*(1 - rgb[1].fY);
-    rgb[2].fX = 50 + 1000*rgb[2].fX;
-    rgb[2].fY = 50 + 1000*(1 - rgb[2].fY);
-
-    // Repeat the first point to connect the polygon.
-    rgb[3] = rgb[0];
-
-    SkPaint paint;
-    canvas.drawPoints(SkCanvas::kPolygon_PointMode, 4, rgb, paint);
-
-    // Finally, encode the result to out.png.
-    SkAutoTUnref<SkData> out(SkImageEncoder::EncodeData(bitmap, SkImageEncoder::kPNG_Type, 100));
+    // Finally, encode the result to the output file.
+    SkAutoTUnref<SkData> out(SkImageEncoder::EncodeData(gamut, SkImageEncoder::kPNG_Type, 100));
     if (!out) {
-        SkDebugf("Failed to encode output.\n");
+        SkDebugf("Failed to encode gamut output.\n");
         return -1;
     }
     SkFILEWStream stream(output);
     bool result = stream.write(out->data(), out->size());
     if (!result) {
-        SkDebugf("Failed to write output.\n");
+        SkDebugf("Failed to write gamut output.\n");
         return -1;
     }
 
+    // Also, if requested, decode and reencode the uncorrected input image.
+    if (!FLAGS_uncorrected.isEmpty()) {
+        SkBitmap bitmap;
+        int width = codec->getInfo().width();
+        int height = codec->getInfo().height();
+        SkAlphaType alphaType = codec->getInfo().alphaType();
+        bitmap.allocN32Pixels(width, height, kOpaque_SkAlphaType == alphaType);
+        SkImageInfo decodeInfo = SkImageInfo::MakeN32(width, height, alphaType);
+        if (SkCodec::kSuccess != codec->getPixels(decodeInfo, bitmap.getPixels(),
+                                                  bitmap.rowBytes())) {
+            SkDebugf("Could not decode input image.\n");
+            return -1;
+        }
+        out.reset(SkImageEncoder::EncodeData(bitmap, SkImageEncoder::kPNG_Type, 100));
+        if (!out) {
+            SkDebugf("Failed to encode uncorrected image.\n");
+            return -1;
+        }
+        SkFILEWStream bitmapStream(FLAGS_uncorrected[0]);
+        result = bitmapStream.write(out->data(), out->size());
+        if (!result) {
+            SkDebugf("Failed to write uncorrected image output.\n");
+            return -1;
+        }
+    }
+
     return 0;
 }