hide SkImageDecoder::Chooser

src/images/SkImageDecoder_libico.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkStream.h"
@@ skipping 76 matching lines @@
     int reserved = read2Bytes(buf, 0);    // 0
     int type = read2Bytes(buf, 2);        // 1
     if (reserved != 0 || type != 1)
         return false;
     int count = read2Bytes(buf, 4);
 
     //need to at least have enough space to hold the initial table of info
     if (length < (size_t)(6 + count*16))
         return false;
 
+#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
     int choice;
     Chooser* chooser = this->getChooser();

[scroggo, 2014/06/11 17:11:23]

ICO is the prime example where the choice actually is meaningful, since an ICO
may contain multiple images - I think other image formats can support this as
well, but I don't know how many images use it in practice, and no clients use
it.

It might be nice to support this feature, but it's reasonable to wait for a
client to request it (which may give us a better idea of what the API should
look like).

     //FIXME:if no chooser, consider providing the largest color image
     //what are the odds that the largest image would be monochrome?
     if (NULL == chooser) {
         choice = 0;
     } else {
         chooser->begin(count);
         for (int i = 0; i < count; i++)
         {
             //need to find out the config, width, and height from the stream
             int width = readByte(buf, 6 + i*16);
@@ skipping 22 matching lines @@
                     continue;
             }
             chooser->inspect(i, c, width, height);
         }
         choice = chooser->choose();
     }
 
     //you never know what the chooser is going to supply
     if (choice >= count || choice < 0)
         return false;
+#else
+    const int choice = 0;   // TODO: fold this value into the expressions below
+#endif
 
     //skip ahead to the correct header
     //commented out lines are not used, but if i switch to other read method, need to know how many to skip
     //otherwise, they could be used for error checking
     int w = readByte(buf, 6 + choice*16);
     int h = readByte(buf, 7 + choice*16);
     int colorCount = readByte(buf, 8 + choice*16);
     //int reservedToo = readByte(buf, 9 + choice*16);   //0
     //int planes = read2Bytes(buf, 10 + choice*16);       //1 - but often 0
     //int fakeBitCount = read2Bytes(buf, 12 + choice*16); //should be real - usually 0
@@ skipping 257 matching lines @@
 static SkImageDecoder_DecodeReg gReg(sk_libico_dfactory);
 
 static SkImageDecoder::Format get_format_ico(SkStreamRewindable* stream) {
     if (is_ico(stream)) {
         return SkImageDecoder::kICO_Format;
     }
     return SkImageDecoder::kUnknown_Format;
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_ico);