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