Merge pull request #4323 from degasus/png

ImageWriter: Don't use inplace alpha truncation.
This commit is contained in:
Markus Wick 2016-10-08 12:10:40 +02:00 committed by GitHub
commit b0acf1bf8f
2 changed files with 22 additions and 11 deletions

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@ -4,6 +4,7 @@
#include <list>
#include <string>
#include <vector>
#include "Common/CommonTypes.h"
#include "Common/FileUtil.h"
@ -27,8 +28,8 @@ Inputs:
data : This is an array of RGBA with 8 bits per channel. 4 bytes for each pixel.
row_stride: Determines the amount of bytes per row of pixels.
*/
bool TextureToPng(u8* data, int row_stride, const std::string& filename, int width, int height,
bool saveAlpha)
bool TextureToPng(const u8* data, int row_stride, const std::string& filename, int width,
int height, bool saveAlpha)
{
bool success = false;
@ -39,6 +40,10 @@ bool TextureToPng(u8* data, int row_stride, const std::string& filename, int wid
char title_key[] = "Title";
png_structp png_ptr = nullptr;
png_infop info_ptr = nullptr;
std::vector<u8> buffer;
if (!saveAlpha)
buffer.resize(width * 4);
// Open file for writing (binary mode)
File::IOFile fp(filename, "wb");
@ -89,15 +94,21 @@ bool TextureToPng(u8* data, int row_stride, const std::string& filename, int wid
// Write image data
for (auto y = 0; y < height; ++y)
{
u8* row_ptr = (u8*)data + y * row_stride;
u8* ptr = row_ptr;
for (auto x = 0; x < row_stride / 4; ++x)
const u8* row_ptr = data + y * row_stride;
if (!saveAlpha)
{
if (!saveAlpha)
ptr[3] = 0xff;
ptr += 4;
for (int x = 0; x < width; x++)
{
for (int i = 0; i < 3; i++)
buffer[4 * x + i] = row_ptr[4 * x + i];
buffer[4 * x + 3] = 0xff;
}
row_ptr = buffer.data();
}
png_write_row(png_ptr, row_ptr);
// The old API uses u8* instead of const u8*. It doesn't write
// to this pointer, but to fit the API, we have to drop the const qualifier.
png_write_row(png_ptr, const_cast<u8*>(row_ptr));
}
// End write

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@ -8,5 +8,5 @@
#include "Common/CommonTypes.h"
bool SaveData(const std::string& filename, const std::string& data);
bool TextureToPng(u8* data, int row_stride, const std::string& filename, int width, int height,
bool saveAlpha = true);
bool TextureToPng(const u8* data, int row_stride, const std::string& filename, int width,
int height, bool saveAlpha = true);