StbImage

A V wrapper of the image loader, writer and resizer from nothings/stb . You can use it to load resize and write images from file or memory.

It is a wrapper for the stb_image.h , stb_image_write.h and stb_image_resize.h files.

library	version used	description
stb_image.h	2.28	image loading/decoding from file/memory: JPG, PNG, TGA, BMP, PSD, GIF, HDR, PIC
stb_image_write.h	1.16	image writing to disk: PNG, TGA, BMP
stb_image_resize.h	0.97	resize images larger/smaller with good quality

Check out nothings/stb for documentation.

Installation

v install Casper64.stbimage

Usage

The library is cross platform so you only need to import it: import casper64.stbimage .

Errors

Some functions return int as result. If the return value is <= 0 an error has occured.

Example:

// load the image
input_image := stbimage.stbi_load('empty.png', width, height, channels, 0)
defer {
    // free the image
    stbimage.stbi_image_free(input_image)
}
if input_image <= 0 {
    // get any errors with `stbimage.get_error()`
    println('Failed to load input image: ${stbimage.get_error()}.')
    return
}

For example run the resize example v run resize.v .

resize.v

module main

import casper64.stbimage

// This program resizes the `v-logo.png` file to 250x250 pixels and outputs it to `out.png`.

[manualfree]
fn main() {
    input_file_name := 'v-logo.png'
    output_file_name := 'out.png'

    // specify new width and height
    new_width := 250
    new_height := 250

    mut width, mut height, mut channels := 0, 0, 0

    // load the image
    input_image := stbimage.stbi_load(input_file_name, width, height, channels, 0)
    defer {
        // free the image
        stbimage.stbi_image_free(input_image)
    }
    if input_image <= 0 {
        println('Failed to load input image: ${stbimage.get_error()}.')
        return
    }

    // Allocate memory for the resized image
    mut output_image := unsafe { malloc(new_width * new_height * channels) }
    if output_image <= 0 {
        eprintln('Failed to allocate memory for the output image.')
        return
    }
    defer {
        // free the allocated data
        unsafe { free(output_image) }
    }

    // Resize the image
    stbimage.stbir_resize_uint8(input_image, width, height, 0, output_image, new_width, new_height,
        0, channels)

    // write the image
    result := stbimage.stbi_write_png(output_file_name, new_width, new_height, channels, output_image,
        new_width * channels)
    if result <= 0 {
        println('Failed to write the output image.')
        return
    }

    println('Image resized and saved successfully.')
}