image: Move image code into its own module.

[apitrace] / image / image.cpp

diff --git a/image/image.cpp b/image/image.cpp
new file mode 100644 (file)
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--- /dev/null
+++ b/image/image.cpp
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+/**************************************************************************
+ *
+ * Copyright 2011 Jose Fonseca
+ * Copyright 2008-2010 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include <assert.h>
+#include <math.h>
+
+#include <algorithm>
+
+#include "image.hpp"
+
+
+namespace image {
+
+
+double Image::compare(Image &ref)
+{
+    if (width != ref.width ||
+        height != ref.height ||
+        channels < 3 ||
+        ref.channels < 3) {
+        return 0.0;
+    }
+
+    // Ignore missing alpha when comparing RGB w/ RGBA, but enforce an equal
+    // number of channels otherwise.
+    unsigned minChannels = std::min(channels, ref.channels);
+    if (channels != ref.channels && minChannels < 3) {
+        return 0.0;
+    }
+
+    const unsigned char *pSrc = start();
+    const unsigned char *pRef = ref.start();
+
+    unsigned long long error = 0;
+    for (unsigned y = 0; y < height; ++y) {
+        for (unsigned  x = 0; x < width; ++x) {
+            // FIXME: Ignore alpha channel until we are able to pick a visual
+            // that matches the traces
+            for (unsigned  c = 0; c < minChannels; ++c) {
+                int delta = pSrc[x*channels + c] - pRef[x*ref.channels + c];
+                error += delta*delta;
+            }
+        }
+
+        pSrc += stride();
+        pRef += ref.stride();
+    }
+
+    double numerator = error*2 + 1;
+    double denominator = height*width*minChannels*255ULL*255ULL*2;
+    double quotient = numerator/denominator;
+
+    // Precision in bits
+    double precision = -log(quotient)/log(2.0);
+
+    return precision;
+}
+
+
+} /* namespace image */