image: reimplement most image merge operations (overlay, screen, etc.).

TODO

@@ -18,17 +18,12 @@ Image:
   - Add gamma handling in pixels.cpp
   - Make some Image::Lock2D method that returns an Array2D
   - port libpipi files:
-     · analysis/histogram.cpp
      · analysis/measure.cpp
      · codec/coreimage.cpp
      · codec/coreimage.h
      · codec/jpeg.cpp
      · combine/blit.cpp
-     · combine/merge.cpp
-     · combine/minmax.cpp
-     · combine/mulscreen.cpp
      · combine/rgb.cpp
-     · combine/subadd.cpp
      · context.cpp
      · filter/blur.cpp
      · filter/rotate.cpp

src/Makefile.am

@@ -111,7 +111,7 @@ liblolcore_sources = \
     sys/thread.cpp sys/threadbase.h \
     \
     image/image.cpp image/image-private.h image/kernel.cpp image/pixel.cpp \
-    image/crop.cpp image/resample.cpp image/noise.cpp \
+    image/crop.cpp image/resample.cpp image/noise.cpp image/combine.cpp \
     image/codec/gdiplus-image.cpp image/codec/imlib2-image.cpp \
     image/codec/sdl-image.cpp image/codec/ios-image.cpp \
     image/codec/zed-image.cpp image/codec/zed-palette-image.cpp \

src/image/combine.cpp

@@ -0,0 +1,155 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2004-2014 Sam Hocevar <sam@hocevar.net>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
+
+/*
+ * Image merge operations: merge, min/max, overlay, screen, multiply,
+ * divide, add, sub, difference
+ */
+
+namespace lol
+{
+
+enum class MergeMode
+{
+    Mix,
+    Min,
+    Max,
+    Overlay,
+    Screen,
+    Divide,
+    Multiply,
+    Add,
+    Sub,
+    Difference,
+};
+
+template<PixelFormat FORMAT, MergeMode MODE>
+static Image GenericMerge(Image &src1, Image &src2, float alpha)
+{
+    typedef typename PixelType<FORMAT>::type pixel_t;
+
+    ASSERT(src1.GetSize() == src2.GetSize());
+    int const count = src1.GetSize().x * src2.GetSize().y;
+
+    Image dst(src1.GetSize());
+
+    pixel_t const *src1p = src1.Lock<FORMAT>();
+    pixel_t const *src2p = src2.Lock<FORMAT>();
+    pixel_t *dstp = dst.Lock<FORMAT>();
+
+    for (int n = 0; n < count; ++n)
+    {
+        if (MODE == MergeMode::Mix)
+            dstp[n] = lol::mix(src1p[n], src2p[n], alpha);
+        else if (MODE == MergeMode::Min)
+            dstp[n] = lol::min(src1p[n], src2p[n]);
+        else if (MODE == MergeMode::Max)
+            dstp[n] = lol::max(src1p[n], src2p[n]);
+        else if (MODE == MergeMode::Overlay)
+            dstp[n] = src1p[n] * (src1p[n] + 2.f * src2p[n]
+                                                 * (pixel_t(1.f) - src1p[n]));
+        else if (MODE == MergeMode::Screen)
+            dstp[n] = src1p[n] + src2p[n] - src1p[n] * src2p[n];
+        else if (MODE == MergeMode::Divide)
+            dstp[n] = src1p[n] / (lol::max(src1p[n], src2p[n]) + pixel_t(1e-8f));
+        else if (MODE == MergeMode::Multiply)
+            dstp[n] = src1p[n] * src2p[n];
+        else if (MODE == MergeMode::Add)
+            dstp[n] = lol::min(src1p[n] + src2p[n], pixel_t(1.f));
+        else if (MODE == MergeMode::Sub)
+            dstp[n] = lol::max(src1p[n] - src2p[n], pixel_t(0.f));
+        else if (MODE == MergeMode::Difference)
+            dstp[n] = lol::abs(src1p[n] - src2p[n]);
+    }
+
+    src1.Unlock(src1p);
+    src2.Unlock(src2p);
+    dst.Unlock(dstp);
+
+    return dst;
+}
+
+template<MergeMode MODE>
+static Image GenericMerge(Image &src1, Image &src2, float alpha)
+{
+    bool gray1 = src1.GetFormat() == PixelFormat::Y_8
+                  || src1.GetFormat() == PixelFormat::Y_F32;
+    bool gray2 = src2.GetFormat() == PixelFormat::Y_8
+                  || src2.GetFormat() == PixelFormat::Y_F32;
+    if (gray1 && gray2)
+        return GenericMerge<PixelFormat::Y_F32, MODE>(src1, src2, alpha);
+    else
+        return GenericMerge<PixelFormat::RGBA_F32, MODE>(src1, src2, alpha);
+
+}
+
+Image Image::Merge(Image &src1, Image &src2, float alpha)
+{
+    return GenericMerge<MergeMode::Mix>(src1, src2, alpha);
+}
+
+Image Image::Mean(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Mix>(src1, src2, 0.5f);
+}
+
+Image Image::Min(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Min>(src1, src2, 0.0f);
+}
+
+Image Image::Max(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Max>(src1, src2, 0.0f);
+}
+
+Image Image::Overlay(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Overlay>(src1, src2, 0.0f);
+}
+
+Image Image::Screen(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Screen>(src1, src2, 0.0f);
+}
+
+Image Image::Divide(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Divide>(src1, src2, 0.0f);
+}
+
+Image Image::Multiply(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Multiply>(src1, src2, 0.0f);
+}
+
+Image Image::Add(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Add>(src1, src2, 0.0f);
+}
+
+Image Image::Sub(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Sub>(src1, src2, 0.0f);
+}
+
+Image Image::Difference(Image &src1, Image &src2)
+{
+    return GenericMerge<MergeMode::Difference>(src1, src2, 0.0f);
+}
+
+} /* namespace lol */
+

src/image/combine/merge.cpp

@@ -1,86 +0,0 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * mean.c: Mean computation function
- */
-
-#include "config.h"
-
-#include <stdlib.h>
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-pipi_image_t *pipi_merge(pipi_image_t *img1, pipi_image_t *img2, double t)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    if(t < 0.0)
-        t = 0.0;
-    else if(t > 1.0)
-        t = 1.0;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-            double t1 = t * img2data[4 * (y * w + x) + 3];
-            double t2 = 1.0 - t1;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = t2 * p + t1 * q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = t2 * p + t1 * q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = t2 * p + t1 * q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = t2 * p + t1 * q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_mean(pipi_image_t *img1, pipi_image_t *img2)
-{
-    return pipi_merge(img1, img2, 0.5);
-}
-

src/image/combine/minmax.cpp

@@ -1,123 +0,0 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * minmax.c: min and max computation functions
- */
-
-#include "config.h"
-
-#include <stdlib.h>
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-pipi_image_t *pipi_min(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p < q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p < q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p < q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p < q ? p : q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_max(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p > q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p > q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p > q ? p : q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p > q ? p : q;
-        }
-    }
-
-    return dst;
-}
-

src/image/combine/mulscreen.cpp

@@ -1,221 +0,0 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * mulscreen.c: multiply and screen computation functions
- */
-
-#include "config.h"
-
-#include <stdlib.h>
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-pipi_image_t *pipi_multiply(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p * q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p * q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p * q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p * q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_divide(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p >= q ? 1. : p / q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p >= q ? 1. : p / q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p >= q ? 1. : p / q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p >= q ? 1. : p / q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_screen(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p + q - p * q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p + q - p * q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p + q - p * q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p + q - p * q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_overlay(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p * (p + 2. * q * (1. - p));
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p * (p + 2. * q * (1. - p));
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p * (p + 2. * q * (1. - p));
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p * (p + 2. * q * (1. - p));
-        }
-    }
-
-    return dst;
-}
-

src/image/combine/subadd.cpp

@@ -1,173 +0,0 @@
-/*
- *  libpipi       Pathetic image processing interface library
- *  Copyright (c) 2004-2008 Sam Hocevar <sam@zoy.org>
- *                All Rights Reserved
- *
- *  $Id$
- *
- *  This library is free software. It comes without any warranty, to
- *  the extent permitted by applicable law. You can redistribute it
- *  and/or modify it under the terms of the Do What The Fuck You Want
- *  To Public License, Version 2, as published by Sam Hocevar. See
- *  http://sam.zoy.org/wtfpl/COPYING for more details.
- */
-
-/*
- * subadd.c: sub, add and difference computation functions
- */
-
-#include "config.h"
-
-#include <stdlib.h>
-#include <math.h>
-
-#include "pipi.h"
-#include "pipi-internals.h"
-
-pipi_image_t *pipi_add(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = (p + q < 1.) ? p + q : 1.;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = (p + q < 1.) ? p + q : 1.;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = (p + q < 1.) ? p + q : 1.;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = (p + q < 1.) ? p + q : 1.;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_sub(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = p < q ? 0 : p - q;
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = p < q ? 0 : p - q;
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = p < q ? 0 : p - q;
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = p < q ? 0 : p - q;
-        }
-    }
-
-    return dst;
-}
-
-pipi_image_t *pipi_difference(pipi_image_t *img1, pipi_image_t *img2)
-{
-    pipi_image_t *dst;
-    pipi_pixels_t *img1p, *img2p, *dstp;
-    float *img1data, *img2data, *dstdata;
-    int x, y, w, h;
-
-    if(img1->w != img2->w || img1->h != img2->h)
-        return NULL;
-
-    w = img1->w;
-    h = img1->h;
-
-    dst = pipi_new(w, h);
-    dstp = pipi_get_pixels(dst, PIPI_PIXELS_RGBA_F32);
-    dstdata = (float *)dstp->pixels;
-
-    img1p = pipi_get_pixels(img1, PIPI_PIXELS_RGBA_F32);
-    img1data = (float *)img1p->pixels;
-    img2p = pipi_get_pixels(img2, PIPI_PIXELS_RGBA_F32);
-    img2data = (float *)img2p->pixels;
-
-    for(y = 0; y < h; y++)
-    {
-        for(x = 0; x < w; x++)
-        {
-            float p, q;
-
-            p = img1data[4 * (y * w + x)];
-            q = img2data[4 * (y * w + x)];
-            dstdata[4 * (y * w + x)] = fabsf(p - q);
-
-            p = img1data[4 * (y * w + x) + 1];
-            q = img2data[4 * (y * w + x) + 1];
-            dstdata[4 * (y * w + x) + 1] = fabsf(p - q);
-
-            p = img1data[4 * (y * w + x) + 2];
-            q = img2data[4 * (y * w + x) + 2];
-            dstdata[4 * (y * w + x) + 2] = fabsf(p - q);
-
-            p = img1data[4 * (y * w + x) + 3];
-            q = img2data[4 * (y * w + x) + 3];
-            dstdata[4 * (y * w + x) + 3] = fabsf(p - q);
-        }
-    }
-
-    return dst;
-}
-

src/lol/image/image.h

@@ -134,6 +134,19 @@ public:
     Image DitherHalftone(float radius, float angle) const;
     Image DitherDbs() const;
 
+    /* Combine images */
+    static Image Merge(Image &src1, Image &src2, float alpha);
+    static Image Mean(Image &src1, Image &src2);
+    static Image Min(Image &src1, Image &src2);
+    static Image Max(Image &src1, Image &src2);
+    static Image Overlay(Image &src1, Image &src2);
+    static Image Screen(Image &src1, Image &src2);
+    static Image Multiply(Image &src1, Image &src2);
+    static Image Divide(Image &src1, Image &src2);
+    static Image Add(Image &src1, Image &src2);
+    static Image Sub(Image &src1, Image &src2);
+    static Image Difference(Image &src1, Image &src2);
+
 private:
     class ImageData *m_data;
 };

src/lolcore.vcxproj

@@ -161,6 +161,7 @@
     <ClCompile Include="image\dither\ostromoukhov.cpp" />
     <ClCompile Include="image\dither\random.cpp" />
     <ClCompile Include="image\crop.cpp" />
+    <ClCompile Include="image\combine.cpp" />
     <ClCompile Include="image\image.cpp" />
     <ClCompile Include="image\kernel.cpp" />
     <ClCompile Include="image\noise.cpp" />

src/lolcore.vcxproj.filters

@@ -309,6 +309,9 @@
     <ClCompile Include="image\color\color.cpp">
       <Filter>image\color</Filter>
     </ClCompile>
+    <ClCompile Include="image\combine.cpp">
+      <Filter>image</Filter>
+    </ClCompile>
     <ClCompile Include="math\geometry.cpp">
       <Filter>math</Filter>
     </ClCompile>