Add libwebp/src/mux/animi.h

Change-Id: I80ca2070d419acf6e8355a295ee965d2df5a4d8f

makefile.unix

@@ -298,6 +298,7 @@ HDRS = \
     src/enc/histogram.h \
     src/enc/vp8enci.h \
     src/enc/vp8li.h \
+    src/mux/animi.h \
     src/mux/muxi.h \
     src/utils/bit_reader.h \
     src/utils/bit_reader_inl.h \

src/mux/Makefile.am

@@ -2,6 +2,7 @@ lib_LTLIBRARIES = libwebpmux.la
 
 libwebpmux_la_SOURCES =
 libwebpmux_la_SOURCES += anim_encode.c
+libwebpmux_la_SOURCES += animi.h
 libwebpmux_la_SOURCES += muxedit.c
 libwebpmux_la_SOURCES += muxi.h
 libwebpmux_la_SOURCES += muxinternal.c

src/mux/anim_encode.c

@@ -16,6 +16,7 @@
 #include <stdio.h>
 #include <stdlib.h>  // for abs()
 
+#include "../mux/animi.h"
 #include "../utils/utils.h"
 #include "../webp/decode.h"
 #include "../webp/encode.h"
@@ -586,6 +587,39 @@ static int GetSubRects(const WebPPicture* const prev_canvas,
                     &params->rect_lossy_, &params->sub_frame_lossy_);
 }
 
+static WEBP_INLINE int clip(int v, int min_v, int max_v) {
+  return (v < min_v) ? min_v : (v > max_v) ? max_v : v;
+}
+
+int WebPAnimEncoderRefineRect(
+    const WebPPicture* const prev_canvas, const WebPPicture* const curr_canvas,
+    int is_lossless, float quality, int* const x_offset, int* const y_offset,
+    int* const width, int* const height) {
+  FrameRect rect;
+  const int right = clip(*x_offset + *width, 0, curr_canvas->width);
+  const int left = clip(*x_offset, 0, curr_canvas->width - 1);
+  const int bottom = clip(*y_offset + *height, 0, curr_canvas->height);
+  const int top = clip(*y_offset, 0, curr_canvas->height - 1);
+  if (prev_canvas == NULL || curr_canvas == NULL ||
+      prev_canvas->width != curr_canvas->width ||
+      prev_canvas->height != curr_canvas->height ||
+      !prev_canvas->use_argb || !curr_canvas->use_argb) {
+    return 0;
+  }
+  rect.x_offset_ = left;
+  rect.y_offset_ = top;
+  rect.width_ = clip(right - left, 0, curr_canvas->width - rect.x_offset_);
+  rect.height_ = clip(bottom - top, 0, curr_canvas->height - rect.y_offset_);
+  MinimizeChangeRectangle(prev_canvas, curr_canvas, &rect, is_lossless,
+                          quality);
+  SnapToEvenOffsets(&rect);
+  *x_offset = rect.x_offset_;
+  *y_offset = rect.y_offset_;
+  *width = rect.width_;
+  *height = rect.height_;
+  return 1;
+}
+
 static void DisposeFrameRectangle(int dispose_method,
                                   const FrameRect* const rect,
                                   WebPPicture* const curr_canvas) {

src/mux/animi.h

@@ -0,0 +1,43 @@
+// Copyright 2016 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.
+// -----------------------------------------------------------------------------
+//
+// Internal header for animation related functions.
+//
+// Author: Hui Su (huisu@google.com)
+
+#ifndef WEBP_MUX_ANIMI_H_
+#define WEBP_MUX_ANIMI_H_
+
+#include "../webp/mux.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Picks the optimal rectangle between two pictures, starting with initial
+// values of offsets and dimensions that are passed in. The initial
+// values will be clipped, if necessary, to make sure the rectangle is
+// within the canvas. "use_argb" must be true for both pictures.
+// Parameters:
+//   prev_canvas, curr_canvas - (in) two input pictures to compare.
+//   is_lossless, quality - (in) encoding settings.
+//   x_offset, y_offset, width, height - (in/out) rectangle between the two
+//                                                input pictures.
+// Returns true on success.
+int WebPAnimEncoderRefineRect(
+    const struct WebPPicture* const prev_canvas,
+    const struct WebPPicture* const curr_canvas,
+    int is_lossless, float quality, int* const x_offset, int* const y_offset,
+    int* const width, int* const height);
+
+#ifdef __cplusplus
+}    // extern "C"
+#endif
+
+#endif  /* WEBP_MUX_ANIMI_H_ */