drop PNGReader and use only PngImageReader

PNGReader is a home-made PNG reader that does not use libpng,
so it's more code, presumably less optimized and it apparently also
doesn't always map colors properly.
The only two features it has that PngImageReader doesn't are explicit
chunk reading (used only for reading Microsoft's GIF in PNG, I
implemented that for PngImageReader in a previous commit), and it
loads paletted images as BitmapEx with a palette instead of
converting to direct-color 24/32bpp or 8bpp-gray. The latter is even
questional if nowadays that's feature or a misfeature, as it saves
memory at the expense of speed. I can implement that if somebody
misses it.
I had to adjust some tests:
- CVE-2016-0952-1.png - invalid CRC of the PNG header, neither Gimp
  nor Gwenview can display that, it should fail
- afl-sample-Z_NEED_DICT.png - failure while decompressing data,
  but the loader considers that only a partially broken image since
  the header is correct, so it "passes" (like in Gimp or Gwenview)
- SdImportTest::testTdf134210() and
  testPictureWithSchemeColor::Load_Verify_Reload_Verify()
  need the colors tested changed, because apparently gamma correction
  or something is now applied correctly, and it wasn't before (again
  checked the loaded images with Gimp)

Change-Id: Id46f8d8a01256daf48ca64264b47c4e609183837
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/112042
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

3 files changed, 6 insertions, 7 deletions

diff --git a/vcl/workben/fftester.cxx b/vcl/workben/fftester.cxx
index 640bd1f54832..7d165d5a5957 100644
--- a/vcl/workben/fftester.cxx
+++ b/vcl/workben/fftester.cxx
@@ -41,7 +41,7 @@
 #include <vcl/dibtools.hxx>
 #include <vcl/event.hxx>
 #include <vcl/graphicfilter.hxx>
-#include <vcl/pngread.hxx>
+#include <vcl/filter/PngImageReader.hxx>
 #include <vcl/svapp.hxx>
 #include <vcl/wmf.hxx>
 #include <vcl/wrkwin.hxx>
@@ -155,8 +155,8 @@ SAL_IMPLEMENT_MAIN_WITH_ARGS(argc, argv)
         else if (strcmp(argv[2], "png") == 0)
         {
             SvFileStream aFileStream(out, StreamMode::READ);
-            vcl::PNGReader aReader(aFileStream);
-            ret = static_cast<int>(!!aReader.Read());
+            vcl::PngImageReader aReader(aFileStream);
+            ret = static_cast<int>(!!aReader.read());
         }
         else if (strcmp(argv[2], "bmp") == 0)
         {
diff --git a/vcl/workben/pngfuzzer.cxx b/vcl/workben/pngfuzzer.cxx
index 2a3357830007..e5e3c9e8a239 100644
--- a/vcl/workben/pngfuzzer.cxx
+++ b/vcl/workben/pngfuzzer.cxx
@@ -8,7 +8,7 @@
  */
 
 #include <tools/stream.hxx>
-#include <vcl/pngread.hxx>
+#include <vcl/filter/PngImageReader.hxx>
 #include "commonfuzzer.hxx"
 
 #include <config_features.h>
@@ -48,8 +48,8 @@ extern "C" void* lo_get_custom_widget_func(const char*)
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
 {
     SvMemoryStream aStream(const_cast<uint8_t*>(data), size, StreamMode::READ);
-    vcl::PNGReader aReader(aStream);
-    (void)aReader.Read();
+    vcl::PngImageReader aReader(aStream);
+    (void)aReader.read();
     return 0;
 }
 
diff --git a/vcl/workben/vcldemo.cxx b/vcl/workben/vcldemo.cxx
index e9df921c293e..e37ac96eba9b 100644
--- a/vcl/workben/vcldemo.cxx
+++ b/vcl/workben/vcldemo.cxx
@@ -39,7 +39,6 @@
 #include <tools/urlobj.hxx>
 #include <tools/stream.hxx>
 #include <vcl/svapp.hxx>
-#include <vcl/pngread.hxx>
 #include <vcl/wrkwin.hxx>
 #include <vcl/virdev.hxx>
 #include <vcl/graphicfilter.hxx>