diff options
| -rw-r--r-- | src/PNGImage.cpp | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/src/PNGImage.cpp b/src/PNGImage.cpp index b70f5ed..b6002ca 100644 --- a/src/PNGImage.cpp +++ b/src/PNGImage.cpp @@ -4,6 +4,7 @@ #include <bitset> #include <cctype> +#include <cmath> #include <cstdint> #include <cstdio> #include <cstdlib> @@ -346,6 +347,14 @@ DEFINE_CHUNK_READER(IEND) uint8_t prior = (y>=1)?imageDataIndex(x, (y-1)):0; imageDataIndex(x, y) = up + prior; } + else if(filterByte(y) == 3) + { + uint8_t avg = pngImageDataIndex(x, y); + uint8_t a = (x>=bpp)?imageDataIndex((x-bpp), y):0; + uint8_t b = (y>=1)?imageDataIndex(x, (y-1)):0; + imageDataIndex(x, y) = avg + std::floor((a + b)/2); + + } else if(filterByte(y) == 4) { uint8_t a = (x>=bpp)?imageDataIndex((x-bpp), y):0; @@ -358,7 +367,7 @@ DEFINE_CHUNK_READER(IEND) else { cout << "No method for filter type: " << (int)filterByte(y) << ", row: " << y << endl; - throw "uh oh"; + throw std::invalid_argument("Filter type not implemented"); } } } |