c++ - 土壤图像尺寸

Question

我能否以某种方式获取图像(任何 SOIL 支持)的大小？

我知道图像文件中有不同的 header 来定义这些尺寸。但是 SOIL 有什么函数可以获取图像大小吗？

Answer 1

SOIL_load_image() 将使用图像的尺寸填充宽度/高度参数，尽管它会完整加载图像:

/**
    Loads an image from disk into an array of unsigned chars.
    Note that *channels return the original channel count of the
    image.  If force_channels was other than SOIL_LOAD_AUTO,
    the resulting image has force_channels, but *channels may be
    different (if the original image had a different channel
    count).
    \return 0 if failed, otherwise returns 1
**/
unsigned char*
    SOIL_load_image
    (
        const char *filename,
        int *width, int *height, int *channels,
        int force_channels
    );

底层stb_image.h has routines不加载完整图像:

// get image dimensions & components without fully decoding
STBIDEF int      stbi_info_from_memory(stbi_uc const *buffer, int len, int *x, int *y, int *comp);
STBIDEF int      stbi_info_from_callbacks(stbi_io_callbacks const *clbk, void *user, int *x, int *y, int *comp);
STBIDEF int      stbi_is_16_bit_from_memory(stbi_uc const *buffer, int len);
STBIDEF int      stbi_is_16_bit_from_callbacks(stbi_io_callbacks const *clbk, void *user);

#ifndef STBI_NO_STDIO
STBIDEF int      stbi_info               (char const *filename,     int *x, int *y, int *comp);
STBIDEF int      stbi_info_from_file     (FILE *f,                  int *x, int *y, int *comp);
STBIDEF int      stbi_is_16_bit          (char const *filename);
STBIDEF int      stbi_is_16_bit_from_file(FILE *f);
#endif