From 1db888ba40c18915b829bb5e108293cdd2f07e88 Mon Sep 17 00:00:00 2001
From: Pascal Massimino <pascal.massimino@gmail.com>
Date: Tue, 27 Mar 2012 12:24:56 +0000
Subject: [PATCH] take colorspace into account when cropping

(cherry picked from commit 4e33653b52637c74ae30adde7990265d1d43994b)

Conflicts:

	src/dec/vp8l.c
---
 src/dec/io.c    | 14 ++++++++------
 src/dec/webp.c  | 11 +++++++----
 src/dec/webpi.h | 10 +++++-----
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/src/dec/io.c b/src/dec/io.c
index 122cf1c6..2760a29d 100644
--- a/src/dec/io.c
+++ b/src/dec/io.c
@@ -468,12 +468,14 @@ static int InitRGBRescaler(const VP8Io* const io, WebPDecParams* const p) {
 
 static int CustomSetup(VP8Io* io) {
   WebPDecParams* const p = (WebPDecParams*)io->opaque;
-  const int is_rgb = (p->output->colorspace < MODE_YUV);
+  const WEBP_CSP_MODE colorspace = p->output->colorspace;
+  const int is_rgb = (colorspace < MODE_YUV);
+  const int is_alpha = IsAlphaMode(colorspace);
 
   p->memory = NULL;
   p->emit = NULL;
   p->emit_alpha = NULL;
-  if (!WebPIoInitFromOptions(p->options, io)) {
+  if (!WebPIoInitFromOptions(p->options, io, is_alpha ? MODE_YUV : MODE_YUVA)) {
     return 0;
   }
 
@@ -502,11 +504,11 @@ static int CustomSetup(VP8Io* io) {
     } else {
       p->emit = EmitYUV;
     }
-    if (IsAlphaMode(p->output->colorspace)) {
-      // We need transparency output
+    if (is_alpha) {  // need transparency output
       p->emit_alpha =
-          is_rgb ? (p->output->colorspace == MODE_RGBA_4444 ?
-              EmitAlphaRGBA4444 : EmitAlphaRGB) : EmitAlphaYUV;
+          is_rgb ? (colorspace == MODE_RGBA_4444 ? EmitAlphaRGBA4444
+                                                 : EmitAlphaRGB)
+                 : EmitAlphaYUV;
     }
   }
 
diff --git a/src/dec/webp.c b/src/dec/webp.c
index c8f9afa1..b995eb3f 100644
--- a/src/dec/webp.c
+++ b/src/dec/webp.c
@@ -613,7 +613,7 @@ VP8StatusCode WebPDecode(const uint8_t* data, uint32_t data_size,
 // Cropping and rescaling.
 
 int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
-                          VP8Io* const io) {
+                          VP8Io* const io, WEBP_CSP_MODE src_colorspace) {
   const int W = io->width;
   const int H = io->height;
   int x = 0, y = 0, w = W, h = H;
@@ -623,9 +623,12 @@ int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
   if (io->use_cropping) {
     w = options->crop_width;
     h = options->crop_height;
-    // TODO(skal): take colorspace into account. Don't assume YUV420.
-    x = options->crop_left & ~1;
-    y = options->crop_top & ~1;
+    x = options->crop_left;
+    y = options->crop_top;
+    if (src_colorspace >= MODE_YUV) {   // only snap for YUV420 or YUV422
+      x &= ~1;
+      y &= ~1;    // TODO(later): only for YUV420, not YUV422.
+    }
     if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > W || y + h > H) {
       return 0;  // out of frame boundary error
     }
diff --git a/src/dec/webpi.h b/src/dec/webpi.h
index a40817b5..1c36abf3 100644
--- a/src/dec/webpi.h
+++ b/src/dec/webpi.h
@@ -121,6 +121,11 @@ VP8StatusCode WebPParseHeaders(const uint8_t** data, uint32_t* data_size,
 // hooks will use the supplied 'params' as io->opaque handle.
 void WebPInitCustomIo(WebPDecParams* const params, VP8Io* const io);
 
+// Setup crop_xxx fields, mb_w and mb_h in io. 'src_colorspace' refers
+// to the *compressed* format, not the output one.
+int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
+                          VP8Io* const io, WEBP_CSP_MODE src_colorspace);
+
 //------------------------------------------------------------------------------
 // Internal functions regarding WebPDecBuffer memory (in buffer.c).
 // Don't really need to be externally visible for now.
@@ -144,12 +149,7 @@ void WebPCopyDecBuffer(const WebPDecBuffer* const src,
 // Copy and transfer ownership from src to dst (beware of parameter order!)
 void WebPGrabDecBuffer(WebPDecBuffer* const src, WebPDecBuffer* const dst);
 
-//------------------------------------------------------------------------------
-// Cropping and rescaling.
 
-// Setup crop_xxx fields, mb_w and mb_h
-int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
-                          VP8Io* const io);
 
 //------------------------------------------------------------------------------