93 lines
3.8 KiB
C++
93 lines
3.8 KiB
C++
#ifndef PNGREAD_HPP
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#define PNGREAD_HPP
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#include <vector>
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#include <string>
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#include <istream>
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namespace Slic3r { namespace png {
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// Interface for an input stream of encoded png image data.
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struct IStream {
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virtual ~IStream() = default;
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virtual size_t read(std::uint8_t *outp, size_t amount) = 0;
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virtual bool is_ok() const = 0;
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};
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// The output format of decode_png: a 2D pixel matrix stored continuously row
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// after row (row major layout).
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template<class PxT> struct Image {
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std::vector<PxT> buf;
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size_t rows, cols;
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PxT get(size_t row, size_t col) const { return buf[row * cols + col]; }
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};
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using ImageGreyscale = Image<uint8_t>;
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// Only decodes true 8 bit grayscale png images. Returns false for other formats
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// TODO (if needed): implement transformation of rgb images into grayscale...
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bool decode_png(IStream &stream, ImageGreyscale &out_img);
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// TODO (if needed)
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// struct RGB { uint8_t r, g, b; };
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// using ImageRGB = Image<RGB>;
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// bool decode_png(IStream &stream, ImageRGB &img);
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// Encoded png data buffer: a simple read-only buffer and its size.
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struct ReadBuf { const void *buf = nullptr; const size_t sz = 0; };
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bool is_png(const ReadBuf &pngbuf);
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template<class Img> bool decode_png(const ReadBuf &in_buf, Img &out_img)
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{
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struct ReadBufStream: public IStream {
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const ReadBuf &rbuf_ref; size_t pos = 0;
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explicit ReadBufStream(const ReadBuf &buf): rbuf_ref{buf} {}
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size_t read(std::uint8_t *outp, size_t amount) override
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{
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if (amount > rbuf_ref.sz - pos) return 0;
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auto buf = static_cast<const std::uint8_t *>(rbuf_ref.buf);
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std::copy(buf + pos, buf + (pos + amount), outp);
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pos += amount;
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return amount;
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}
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bool is_ok() const override { return pos < rbuf_ref.sz; }
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} stream{in_buf};
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return decode_png(stream, out_img);
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}
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// TODO: std::istream of FILE* could be similarly adapted in case its needed...
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// Down to earth function to store a packed RGB image to file. Mostly useful for debugging purposes.
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bool write_rgb_to_file(const char *file_name_utf8, size_t width, size_t height, const uint8_t *data_rgb);
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bool write_rgb_to_file(const std::string &file_name_utf8, size_t width, size_t height, const uint8_t *data_rgb);
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bool write_rgb_to_file(const std::string &file_name_utf8, size_t width, size_t height, const std::vector<uint8_t> &data_rgb);
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// Grayscale variants
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bool write_gray_to_file(const char *file_name_utf8, size_t width, size_t height, const uint8_t *data_gray);
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bool write_gray_to_file(const std::string &file_name_utf8, size_t width, size_t height, const uint8_t *data_gray);
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bool write_gray_to_file(const std::string &file_name_utf8, size_t width, size_t height, const std::vector<uint8_t> &data_gray);
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// Scaled variants are mostly useful for debugging purposes, for example to export images of low resolution distance fileds.
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// Scaling is done by multiplying rows and columns without any smoothing to emphasise the original pixels.
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bool write_rgb_to_file_scaled(const char *file_name_utf8, size_t width, size_t height, const uint8_t *data_rgb, size_t scale);
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bool write_rgb_to_file_scaled(const std::string &file_name_utf8, size_t width, size_t height, const uint8_t *data_rgb, size_t scale);
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bool write_rgb_to_file_scaled(const std::string &file_name_utf8, size_t width, size_t height, const std::vector<uint8_t> &data_rgb, size_t scale);
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// Grayscale variants
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bool write_gray_to_file_scaled(const char *file_name_utf8, size_t width, size_t height, const uint8_t *data_gray, size_t scale);
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bool write_gray_to_file_scaled(const std::string &file_name_utf8, size_t width, size_t height, const uint8_t *data_gray, size_t scale);
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bool write_gray_to_file_scaled(const std::string &file_name_utf8, size_t width, size_t height, const std::vector<uint8_t> &data_gray, size_t scale);
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}} // namespace Slic3r::png
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#endif // PNGREAD_HPP
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