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// pngreader.h - Public Domain - see unlicense at bottom of pvpngreader.cpp
#pragma once
#include <stdint.h>
namespace pv_png
{
// PNG color types
enum
{
PNG_COLOR_TYPE_GREYSCALE = 0,
PNG_COLOR_TYPE_TRUECOLOR = 2,
PNG_COLOR_TYPE_PALETTIZED = 3,
PNG_COLOR_TYPE_GREYSCALE_ALPHA = 4,
PNG_COLOR_TYPE_TRUECOLOR_ALPHA = 6
};
// PNG file description
struct png_info
{
uint32_t m_width;
uint32_t m_height;
uint32_t m_num_chans; // The number of channels, factoring in transparency. Ranges from [1-4].
uint32_t m_bit_depth; // PNG ihdr bit depth: 1, 2, 4, 8 or 16
uint32_t m_color_type; // PNG ihdr color type, PNG_COLOR_TYPE_GRAYSCALE etc.
bool m_has_gamma; // true if the PNG file had a GAMA chunk
uint32_t m_gamma_value; // PNG GAMA chunk value, scaled by 100000
bool m_has_trns; // true if the PNG file used colorkey transparency
};
// Retrieved information about the PNG file.
// Returns false on any errors.
bool get_png_info(const void* pImage_buf, size_t buf_size, png_info& info);
// Input parameters:
// pImage_buf, buf_size - pointer to PNG image data
// desired_chans - desired number of output channels. 0=auto, 1=grayscale, 2=grayscale alpha, 3=24bpp RGB, 4=32bpp RGBA
//
// Output parameters:
// width, height - PNG image resolution
// num_chans - actual number of channels in PNG, from [1,4] (factoring in transparency)
//
// Returns nullptr on any errors.
void* load_png(const void* pImage_buf, size_t buf_size, uint32_t desired_chans, uint32_t &width, uint32_t &height, uint32_t& num_chans);
}
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