Replace int flags with struct FXDIB_ResampleOptions.

Using bit values in an int may not be reliable, since different parts of
the code can interpret the bits differently. e.g. FXDIB_DOWNSAMPLE and
RENDER_FORCE_DOWNSAMPLE are defined in different places, but can be used
interchangeably because they just happen to have the same value. It
works but is rather fragile.

Instead, use a struct of bools to explicitly define what different bits
mean. Remove FXDIB_DOWNSAMPLE and friends.

Change-Id: I9cf0c8f94d1ed27edf8dba22b0ab0ee67f2722cc
Reviewed-on: https://pdfium-review.googlesource.com/c/44650
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 22 insertions, 4 deletions

diff --git a/core/fxge/fx_dib.h b/core/fxge/fx_dib.h
index 221a05278f..8cb7040f5a 100644
--- a/core/fxge/fx_dib.h
+++ b/core/fxge/fx_dib.h
@@ -46,10 +46,28 @@ using FX_CMYK = uint32_t;
 
 extern const int16_t SDP_Table[513];
 
-#define FXDIB_DOWNSAMPLE 0x04
-#define FXDIB_INTERPOL 0x20
-#define FXDIB_BICUBIC_INTERPOL 0x80
-#define FXDIB_NOSMOOTH 0x100
+struct FXDIB_ResampleOptions {
+  FXDIB_ResampleOptions();
+  // TODO(thestig): Remove this ctor once C++14 can be used for more flexible
+  // constexpr initialization.
+  FXDIB_ResampleOptions(bool downsample,
+                        bool bilinear,
+                        bool bicubic,
+                        bool halftone,
+                        bool no_smoothing,
+                        bool lossy);
+
+  bool HasAnyOptions() const;
+
+  bool bInterpolateDownsample = false;
+  bool bInterpolateBilinear = false;
+  bool bInterpolateBicubic = false;
+  bool bHalftone = false;
+  bool bNoSmoothing = false;
+  bool bLossy = false;
+};
+
+extern const FXDIB_ResampleOptions kBilinearInterpolation;
 
 // See PDF 1.7 spec, table 7.2 and 7.3. The enum values need to be in the same
 // order as listed in the spec.