libwebp: update to 0.4.3

This commit imports libwebp 0.4.3, including AUTHORS, COPYING, ChangeLog,
NEWS, PATENTS, README and src directories. In src, only includes header
and source files.

The patches required to build it in Qt will follow in separate
commit(s).

Change-Id: I23ebfd69e47a468c91a9e9b109e9cb8ac63705d4
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: aavit <eirik.aavitsland@theqtcompany.com>

1 files changed, 206 insertions, 0 deletions

diff --git a/src/3rdparty/libwebp/src/enc/picture_tools.c b/src/3rdparty/libwebp/src/enc/picture_tools.c
new file mode 100644
index 0000000..7c73646
--- /dev/null
+++ b/src/3rdparty/libwebp/src/enc/picture_tools.c
@@ -0,0 +1,206 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// WebPPicture tools: alpha handling, etc.
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./vp8enci.h"
+#include "../dsp/yuv.h"
+
+static WEBP_INLINE uint32_t MakeARGB32(int r, int g, int b) {
+  return (0xff000000u | (r << 16) | (g << 8) | b);
+}
+
+//------------------------------------------------------------------------------
+// Helper: clean up fully transparent area to help compressibility.
+
+#define SIZE 8
+#define SIZE2 (SIZE / 2)
+static int is_transparent_area(const uint8_t* ptr, int stride, int size) {
+  int y, x;
+  for (y = 0; y < size; ++y) {
+    for (x = 0; x < size; ++x) {
+      if (ptr[x]) {
+        return 0;
+      }
+    }
+    ptr += stride;
+  }
+  return 1;
+}
+
+static int is_transparent_argb_area(const uint32_t* ptr, int stride, int size) {
+  int y, x;
+  for (y = 0; y < size; ++y) {
+    for (x = 0; x < size; ++x) {
+      if (ptr[x] & 0xff000000u) {
+        return 0;
+      }
+    }
+    ptr += stride;
+  }
+  return 1;
+}
+
+static void flatten(uint8_t* ptr, int v, int stride, int size) {
+  int y;
+  for (y = 0; y < size; ++y) {
+    memset(ptr, v, size);
+    ptr += stride;
+  }
+}
+
+static void flatten_argb(uint32_t* ptr, uint32_t v, int stride, int size) {
+  int x, y;
+  for (y = 0; y < size; ++y) {
+    for (x = 0; x < size; ++x) ptr[x] = v;
+    ptr += stride;
+  }
+}
+
+void WebPCleanupTransparentArea(WebPPicture* pic) {
+  int x, y, w, h;
+  if (pic == NULL) return;
+  w = pic->width / SIZE;
+  h = pic->height / SIZE;
+
+  // note: we ignore the left-overs on right/bottom
+  if (pic->use_argb) {
+    uint32_t argb_value = 0;
+    for (y = 0; y < h; ++y) {
+      int need_reset = 1;
+      for (x = 0; x < w; ++x) {
+        const int off = (y * pic->argb_stride + x) * SIZE;
+        if (is_transparent_argb_area(pic->argb + off, pic->argb_stride, SIZE)) {
+          if (need_reset) {
+            argb_value = pic->argb[off];
+            need_reset = 0;
+          }
+          flatten_argb(pic->argb + off, argb_value, pic->argb_stride, SIZE);
+        } else {
+          need_reset = 1;
+        }
+      }
+    }
+  } else {
+    const uint8_t* const a_ptr = pic->a;
+    int values[3] = { 0 };
+    if (a_ptr == NULL) return;    // nothing to do
+    for (y = 0; y < h; ++y) {
+      int need_reset = 1;
+      for (x = 0; x < w; ++x) {
+        const int off_a = (y * pic->a_stride + x) * SIZE;
+        const int off_y = (y * pic->y_stride + x) * SIZE;
+        const int off_uv = (y * pic->uv_stride + x) * SIZE2;
+        if (is_transparent_area(a_ptr + off_a, pic->a_stride, SIZE)) {
+          if (need_reset) {
+            values[0] = pic->y[off_y];
+            values[1] = pic->u[off_uv];
+            values[2] = pic->v[off_uv];
+            need_reset = 0;
+          }
+          flatten(pic->y + off_y, values[0], pic->y_stride, SIZE);
+          flatten(pic->u + off_uv, values[1], pic->uv_stride, SIZE2);
+          flatten(pic->v + off_uv, values[2], pic->uv_stride, SIZE2);
+        } else {
+          need_reset = 1;
+        }
+      }
+    }
+  }
+}
+
+#undef SIZE
+#undef SIZE2
+
+//------------------------------------------------------------------------------
+// Blend color and remove transparency info
+
+#define BLEND(V0, V1, ALPHA) \
+    ((((V0) * (255 - (ALPHA)) + (V1) * (ALPHA)) * 0x101) >> 16)
+#define BLEND_10BIT(V0, V1, ALPHA) \
+    ((((V0) * (1020 - (ALPHA)) + (V1) * (ALPHA)) * 0x101) >> 18)
+
+void WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb) {
+  const int red = (background_rgb >> 16) & 0xff;
+  const int green = (background_rgb >> 8) & 0xff;
+  const int blue = (background_rgb >> 0) & 0xff;
+  int x, y;
+  if (pic == NULL) return;
+  if (!pic->use_argb) {
+    const int uv_width = (pic->width >> 1);  // omit last pixel during u/v loop
+    const int Y0 = VP8RGBToY(red, green, blue, YUV_HALF);
+    // VP8RGBToU/V expects the u/v values summed over four pixels
+    const int U0 = VP8RGBToU(4 * red, 4 * green, 4 * blue, 4 * YUV_HALF);
+    const int V0 = VP8RGBToV(4 * red, 4 * green, 4 * blue, 4 * YUV_HALF);
+    const int has_alpha = pic->colorspace & WEBP_CSP_ALPHA_BIT;
+    if (!has_alpha || pic->a == NULL) return;    // nothing to do
+    for (y = 0; y < pic->height; ++y) {
+      // Luma blending
+      uint8_t* const y_ptr = pic->y + y * pic->y_stride;
+      uint8_t* const a_ptr = pic->a + y * pic->a_stride;
+      for (x = 0; x < pic->width; ++x) {
+        const int alpha = a_ptr[x];
+        if (alpha < 0xff) {
+          y_ptr[x] = BLEND(Y0, y_ptr[x], a_ptr[x]);
+        }
+      }
+      // Chroma blending every even line
+      if ((y & 1) == 0) {
+        uint8_t* const u = pic->u + (y >> 1) * pic->uv_stride;
+        uint8_t* const v = pic->v + (y >> 1) * pic->uv_stride;
+        uint8_t* const a_ptr2 =
+            (y + 1 == pic->height) ? a_ptr : a_ptr + pic->a_stride;
+        for (x = 0; x < uv_width; ++x) {
+          // Average four alpha values into a single blending weight.
+          // TODO(skal): might lead to visible contouring. Can we do better?
+          const int alpha =
+              a_ptr[2 * x + 0] + a_ptr[2 * x + 1] +
+              a_ptr2[2 * x + 0] + a_ptr2[2 * x + 1];
+          u[x] = BLEND_10BIT(U0, u[x], alpha);
+          v[x] = BLEND_10BIT(V0, v[x], alpha);
+        }
+        if (pic->width & 1) {   // rightmost pixel
+          const int alpha = 2 * (a_ptr[2 * x + 0] + a_ptr2[2 * x + 0]);
+          u[x] = BLEND_10BIT(U0, u[x], alpha);
+          v[x] = BLEND_10BIT(V0, v[x], alpha);
+        }
+      }
+      memset(a_ptr, 0xff, pic->width);
+    }
+  } else {
+    uint32_t* argb = pic->argb;
+    const uint32_t background = MakeARGB32(red, green, blue);
+    for (y = 0; y < pic->height; ++y) {
+      for (x = 0; x < pic->width; ++x) {
+        const int alpha = (argb[x] >> 24) & 0xff;
+        if (alpha != 0xff) {
+          if (alpha > 0) {
+            int r = (argb[x] >> 16) & 0xff;
+            int g = (argb[x] >>  8) & 0xff;
+            int b = (argb[x] >>  0) & 0xff;
+            r = BLEND(red, r, alpha);
+            g = BLEND(green, g, alpha);
+            b = BLEND(blue, b, alpha);
+            argb[x] = MakeARGB32(r, g, b);
+          } else {
+            argb[x] = background;
+          }
+        }
+      }
+      argb += pic->argb_stride;
+    }
+  }
+}
+
+#undef BLEND
+#undef BLEND_10BIT
+
+//------------------------------------------------------------------------------