1 files changed, 137 insertions, 0 deletions
diff --git a/src/mpc-hc/ImageGrayer.cpp b/src/mpc-hc/ImageGrayer.cpp
new file mode 100644
index 000000000..67e4074cf
--- /dev/null
+++ b/src/mpc-hc/ImageGrayer.cpp
@@ -0,0 +1,137 @@
+/*
+* (C) 2016 see Authors.txt
+*
+* This file is part of MPC-HC.
+*
+* MPC-HC is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation; either version 3 of the License, or
+* (at your option) any later version.
+*
+* MPC-HC is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+*/
+
+#include "stdafx.h"
+#include "ImageGrayer.h"
+
+struct HLS {
+    double H, L, S;
+
+    HLS(const RGBQUAD& rgb) {
+        double R = rgb.rgbRed / 255.0;
+        double G = rgb.rgbGreen / 255.0;
+        double B = rgb.rgbBlue / 255.0;
+        double max = std::max({ R, G, B });
+        double min = std::min({ R, G, B });
+
+        L = (max + min) / 2.0;
+
+        if (max == min) {
+            S = H = 0.0;
+        } else {
+            double d = max - min;
+
+            S = (L < 0.5) ? (d / (max + min)) : (d / (2.0 - max - min));
+
+            if (R == max) {
+                H = (G - B) / d;
+            } else if (G == max) {
+                H = 2.0 + (B - R) / d;
+            } else { // if (B == max)
+                H = 4.0 + (R - G) / d;
+            }
+            H /= 6.0;
+            if (H < 0.0) {
+                H += 1.0;
+            }
+        }
+    }
+
+    RGBQUAD toRGBQUAD() {
+        RGBQUAD rgb;
+        rgb.rgbReserved = 255;
+
+        if (S == 0.0) {
+            rgb.rgbRed = rgb.rgbGreen = rgb.rgbBlue = BYTE(L * 255);
+        } else {
+            auto hue2rgb = [](double p, double q, double h) {
+                if (h < 0.0) {
+                    h += 1.0;
+                } else if (h > 1.0) {
+                    h -= 1.0;
+                }
+
+                if (h < 1.0 / 6.0) {
+                    return p + (q - p) * 6.0 * h;
+                } else if (h < 0.5) {
+                    return q;
+                } else if (h < 2.0 / 3.0) {
+                    return p + (q - p) * (2.0 / 3.0 - h) * 6.0;
+                }
+                return p;
+            };
+
+            double q = (L < 0.5) ? (L * (1 + S)) : (L + S - L * S);
+            double p = 2 * L - q;
+
+            rgb.rgbRed = BYTE(hue2rgb(p, q, H + 1.0 / 3.0) * 255);
+            rgb.rgbGreen = BYTE(hue2rgb(p, q, H) * 255);
+            rgb.rgbBlue = BYTE(hue2rgb(p, q, H - 1.0 / 3.0) * 255);
+        }
+
+        return rgb;
+    }
+};
+
+bool ImageGrayer::Gray(const CImage& imgSource, CImage& imgDest)
+{
+    // Only support 32-bit image for now
+    if (imgSource.GetBPP() != 32) {
+        return false;
+    }
+
+    imgDest.Destroy();
+    if (!imgDest.Create(imgSource.GetWidth(), imgSource.GetHeight(), imgSource.GetBPP())) {
+        return false;
+    }
+    BOOL bCopied = imgSource.BitBlt(imgDest.GetDC(), 0, 0);
+    imgDest.ReleaseDC();
+    if (!bCopied) {
+        return false;
+    }
+
+    auto adjustBrightness = [](BYTE c, double p) {
+        int cAdjusted;
+        if (c == 0 && p > 1.0) {
+            cAdjusted = std::lround((p - 1.0) * 255);
+        } else {
+            cAdjusted = std::lround(c * p);
+        }
+
+        return BYTE(std::min(cAdjusted, 255));
+    };
+
+    BYTE* bits = static_cast<BYTE*>(imgDest.GetBits());
+    for (int y = 0; y < imgDest.GetHeight(); y++, bits += imgDest.GetPitch()) {
+        RGBQUAD* p = reinterpret_cast<RGBQUAD*>(bits);
+        for (int x = 0; x < imgDest.GetWidth(); x++) {
+            HLS hls(p[x]);
+            hls.S = 0.0; // Make the color gray
+
+            RGBQUAD rgb = hls.toRGBQUAD();
+
+            p[x].rgbRed = BYTE(adjustBrightness(rgb.rgbRed, 1.5) * p[x].rgbReserved / 255);
+            p[x].rgbGreen = BYTE(adjustBrightness(rgb.rgbGreen, 1.5) * p[x].rgbReserved / 255);
+            p[x].rgbBlue = BYTE(adjustBrightness(rgb.rgbBlue, 1.5) * p[x].rgbReserved / 255);
+        }
+    }
+
+    return true;
+}