image.h

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#pragma once
 
#include <scimesh/types.h>
#include <vector>
#include <cstdint>
#include <string>
 
namespace scimesh {
 
// ---------------------------------------------------------------------------
//  Enums for image operations
// ---------------------------------------------------------------------------
 
enum class MergeDirection {
    LEFT,   
    RIGHT,  
    TOP,    
    BOTTOM  
};
 
enum class CropContentDirection {
    LEFT,       
    RIGHT,      
    HORIZONTAL, 
    TOP,        
    BOTTOM,     
    VERTICAL,   
    ALL         
};
 
enum class FitMode {
    PAD,   
    SCALE  
};
 
// ---------------------------------------------------------------------------
//  Image
// ---------------------------------------------------------------------------
 
struct Image {
    int width = 0;
 
    int height = 0;
 
    std::vector<uint8_t> pixels;
 
    Image() = default;
 
    Image(int w, int h);
 
    void set_pixel(int x, int y, uint8_t r, uint8_t g, uint8_t b, uint8_t a);
 
    void get_pixel(int x, int y, uint8_t &r, uint8_t &g, uint8_t &b, uint8_t &a) const;
 
    void clear(uint8_t r, uint8_t g, uint8_t b, uint8_t a);
 
    void clear_float(float r, float g, float b, float a);
 
    Color sample_bilinear(float u, float v) const;
 
    Image downsample_box(int factor) const;
 
    void crop(int x, int y, int w, int h);
 
    void merge(const Image &other, MergeDirection direction);
 
    void grow(int top, int bottom, int left, int right, const Color &background);
 
    void rotate_90(bool clockwise = true);
 
    void scale(int new_width, int new_height);
 
    void crop_to_content(CropContentDirection direction, const Color &background);
 
    void apply_contrast(float contrast);
 
    // ------------------------------------------------------------------
    //  File output
    // ------------------------------------------------------------------
 
    bool write_ppm(const std::string &filename) const;
 
    bool write_bmp(const std::string &filename) const;
 
    bool write_tga(const std::string &filename, bool use24bit = false) const;
 
    bool write_png(const std::string &filename) const;
 
    // ------------------------------------------------------------------
    //  File input (stb_image)
    // ------------------------------------------------------------------
 
    static Image read_image(const std::string &path);
 
    // ------------------------------------------------------------------
    //  Size normalization
    // ------------------------------------------------------------------
 
    void pad_to_size(int target_w, int target_h, const Color &background);
};
 
// ---------------------------------------------------------------------------
//  Free functions
// ---------------------------------------------------------------------------
 
Image grid_arrange(const std::vector<Image> &images,
                   int ncol = 0, int nrow = 0,
                   FitMode fit_mode = FitMode::PAD,
                   const Color &background = Color(1.0f, 1.0f, 1.0f, 1.0f));
 
inline Image stack_horizontal(const std::vector<Image> &images,
                               FitMode fit_mode = FitMode::PAD,
                               const Color &background = Color(1.0f, 1.0f, 1.0f, 1.0f)) {
    return grid_arrange(images, static_cast<int>(images.size()), 1,
                        fit_mode, background);
}
 
inline Image stack_vertical(const std::vector<Image> &images,
                             FitMode fit_mode = FitMode::PAD,
                             const Color &background = Color(1.0f, 1.0f, 1.0f, 1.0f)) {
    return grid_arrange(images, 1, static_cast<int>(images.size()),
                        fit_mode, background);
}
 
} // namespace scimesh