gm: add a flag to force perspective usage in all gms

gm/gmmain.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * Code for the "gm" (Golden Master) rendering comparison tool.
  *
@@ skipping 1405 matching lines @@
              "each test).");
 DEFINE_bool(writeChecksumBasedFilenames, false, "When writing out actual images, use checksum-"
             "based filenames, as rebaseline.py will use when downloading them from Google Storage");
 DEFINE_string(writeJsonSummaryPath, "", "Write a JSON-formatted result summary to this file.");
 DEFINE_string2(writePath, w, "",  "Write rendered images into this directory.");
 DEFINE_string2(writePicturePath, p, "", "Write .skp files into this directory.");
 DEFINE_int32(pdfJpegQuality, -1, "Encodes images in JPEG at quality level N, "
              "which can be in range 0-100). N = -1 will disable JPEG compression. "
              "Default is N = 100, maximum quality.");
 
+// TODO(edisonn): pass a matrix instead of forcePerspectiveMatrix
+// Either the 9 numbers defining the matrix
+// or probably more readable would be to replace it with a set of a few predicates
+// Like --prerotate 100 200 10 --posttranslate 10, 10
+// Probably define spacial names like centerx, centery, top, bottom, left, right
+// then we can write something reabable like --rotate centerx centery 90
+DEFINE_bool(forcePerspectiveMatrix, false, "Force a perspective matrix.");
+
 static bool encode_to_dct_stream(SkWStream* stream, const SkBitmap& bitmap, const SkIRect& rect) {
     // Filter output of warnings that JPEG is not available for the image.
     if (bitmap.width() >= 65500 || bitmap.height() >= 65500) return false;
     if (FLAGS_pdfJpegQuality == -1) return false;
 
     SkIRect bitmapBounds;
     SkBitmap subset;
     const SkBitmap* bitmapToUse = &bitmap;
     bitmap.getBounds(&bitmapBounds);
     if (rect != bitmapBounds) {
@@ skipping 711 matching lines @@
     if (NULL != gmmain.fMissingExpectationsPath) {
         if (!prepare_subdirectories(gmmain.fMissingExpectationsPath, gmmain.fUseFileHierarchy,
                                     configs, pdfRasterizers)) {
             return -1;
         }
     }
 
     Iter iter;
     GM* gm;
     while ((gm = iter.next()) != NULL) {
+        if (FLAGS_forcePerspectiveMatrix) {
+            SkMatrix perspective;
+            perspective.setIdentity();
+            perspective.setPerspY(SkScalarDiv(SK_Scalar1, SkIntToScalar(1000)));
+            perspective.setSkewX(SkScalarDiv(SkIntToScalar(8),
+                                 SkIntToScalar(25)));
+
+            gm->setStarterMatrix(perspective);
+        }        
         SkAutoTDelete<GM> adgm(gm);
         ++gmIndex;
         if (moduloRemainder >= 0) {
             if ((gmIndex % moduloDivisor) != moduloRemainder) {
                 continue;
             }
             moduloStr.printf("[%d.%d] ", gmIndex, moduloDivisor);
         }
 
         const char* shortName = gm->shortName();
@@ skipping 87 matching lines @@
     if (FLAGS_forceBWtext) {
         canvas->setDrawFilter(SkNEW(BWTextDrawFilter))->unref();
     }
 }
 
 #if !defined(SK_BUILD_FOR_IOS) && !defined(SK_BUILD_FOR_NACL)
 int main(int argc, char * const argv[]) {
     return tool_main(argc, (char**) argv);
 }
 #endif