stbi.c.v

// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.

module stbi

@[if trace_stbi_allocations ?]
fn trace_allocation(message string) {
	eprintln(message)
}

@[export: 'stbi__callback_malloc']
fn cb_malloc(s usize) voidptr {
	res := unsafe { malloc(isize(s)) }
	trace_allocation('> stbi__callback_malloc: ${s} => ${ptr_str(res)}')
	return res
}

@[export: 'stbi__callback_realloc']
fn cb_realloc(p voidptr, s usize) voidptr {
	res := unsafe { v_realloc(p, isize(s)) }
	trace_allocation('> stbi__callback_realloc: ${ptr_str(p)} , ${s} => ${ptr_str(res)}')
	return res
}

@[export: 'stbi__callback_free']
fn cb_free(p voidptr) {
	trace_allocation('> stbi__callback_free: ${ptr_str(p)}')
	unsafe { free(p) }
}

#flag -I @VEXEROOT/thirdparty/stb_image
#include "stb_image.h"
#include "stb_image_write.h"
#include "stb_image_resize2.h"
#include "stb_v_header.h"
#flag @VEXEROOT/thirdparty/stb_image/stbi.o

pub struct Image {
pub mut:
	width       int
	height      int
	nr_channels int
	ok          bool
	data        &u8 = unsafe { nil }
	ext         string
}

//-----------------------------------------------------------------------------
//
// Configuration functions
//
//-----------------------------------------------------------------------------
fn C.stbi_set_flip_vertically_on_load(should_flip int)
fn C.stbi_flip_vertically_on_write(flag int)
fn C.set_png_compression_level(level int)
fn C.write_force_png_filter(level int)
fn C.write_tga_with_rle(level int)

pub fn set_flip_vertically_on_load(val bool) {
	C.stbi_set_flip_vertically_on_load(val)
}

pub fn set_flip_vertically_on_write(val bool) {
	C.stbi_flip_vertically_on_write(val)
}

// set_png_compression_level set the PNG compression level during the writing process
// defaults to 8; set to higher for more compression
pub fn set_png_compression_level(level int) {
	C.set_png_compression_level(level)
}

// write_force_png_filter defaults to -1; set to 0..5 to force a filter mode
// the filter algorithms that can be applied before compression. The purpose of these filters is to prepare the image data for optimum compression.
// Type    Name
//
// 0       None
// 1       Sub
// 2       Up
// 3       Average
// 4       Paeth
pub fn write_force_png_filter(level int) {
	C.write_force_png_filter(level)
}

// stbi_write_tga_with_rle enable/disable the TGA RLE during the writing process
// defaults to true; set to false to disable RLE in tga
pub fn write_tga_with_rle(flag bool) {
	C.write_tga_with_rle(if flag { 1 } else { 0 })
}

//-----------------------------------------------------------------------------
//
// Utility functions
//
//-----------------------------------------------------------------------------
fn C.stbi_image_free(retval_from_stbi_load &u8)

pub fn (img &Image) free() {
	C.stbi_image_free(img.data)
}

//-----------------------------------------------------------------------------
//
// Load functions
//
//-----------------------------------------------------------------------------
fn C.stbi_load(filename &char, x &int, y &int, channels_in_file &int, desired_channels int) &u8
fn C.stbi_load_from_file(f voidptr, x &int, y &int, channels_in_file &int, desired_channels int) &u8
fn C.stbi_load_from_memory(buffer &u8, len int, x &int, y &int, channels_in_file &int, desired_channels int) &u8

@[params]
pub struct LoadParams {
pub:
	// the number of channels you expect the image to have.
	// If set to 0 stbi will figure out the correct number of channels
	desired_channels int = C.STBI_rgb_alpha
}

// load load an image from a path
pub fn load(path string, params LoadParams) !Image {
	ext := path.all_after_last('.')
	mut res := Image{
		ok:  true
		ext: ext
	}
	res.data = C.stbi_load(&char(path.str), &res.width, &res.height, &res.nr_channels,
		params.desired_channels)

	if isnil(res.data) {
		return error('stbi_image failed to load from "${path}"')
	}
	return res
}

// load_from_memory load an image from a memory buffer
pub fn load_from_memory(buf &u8, bufsize int, params LoadParams) !Image {
	mut res := Image{
		ok: true
	}
	res.data = C.stbi_load_from_memory(buf, bufsize, &res.width, &res.height, &res.nr_channels,
		params.desired_channels)
	if isnil(res.data) {
		return error('stbi_image failed to load from memory')
	}
	return res
}

//-----------------------------------------------------------------------------
//
// Resize functions
//
//-----------------------------------------------------------------------------
fn C.stbir_resize_uint8_linear(input_pixels &u8, input_w int, input_h int, input_stride_in_bytes int, output_pixels &u8,
	output_w int, output_h int, output_stride_in_bytes int, num_channels int) int

// resize_uint8 resizes `img` to dimensions of `output_w` and `output_h`
pub fn resize_uint8(img &Image, output_w int, output_h int) !Image {
	mut res := Image{
		ok:          true
		ext:         img.ext
		width:       output_w
		height:      output_h
		nr_channels: img.nr_channels
	}

	res.data = cb_malloc(usize(output_w * output_h * img.nr_channels))
	if res.data == 0 {
		return error('stbi_image failed to resize file')
	}

	if 0 == C.stbir_resize_uint8_linear(img.data, img.width, img.height, 0, res.data,
		output_w, output_h, 0, img.nr_channels) {
		return error('stbi_image failed to resize file')
	}
	return res
}

//-----------------------------------------------------------------------------
//
// Write functions
//
//-----------------------------------------------------------------------------
fn C.stbi_write_png(filename &char, w int, h int, comp int, buffer &u8, stride_in_bytes int) int
fn C.stbi_write_bmp(filename &char, w int, h int, comp int, buffer &u8) int
fn C.stbi_write_tga(filename &char, w int, h int, comp int, buffer &u8) int
fn C.stbi_write_jpg(filename &char, w int, h int, comp int, buffer &u8, quality int) int

// fn C.stbi_write_hdr(filename &char, w int, h int, comp int, buffer &u8) int // buffer &u8 => buffer &f32

// stbi_write_png write on path a PNG file
// row_stride_in_bytes is usually equal to: w * comp
pub fn stbi_write_png(path string, w int, h int, comp int, buf &u8, row_stride_in_bytes int) ! {
	if 0 == C.stbi_write_png(&char(path.str), w, h, comp, buf, row_stride_in_bytes) {
		return error('stbi_image failed to write png file to "${path}"')
	}
}

// stbi_write_png write on path a BMP file
pub fn stbi_write_bmp(path string, w int, h int, comp int, buf &u8) ! {
	if 0 == C.stbi_write_bmp(&char(path.str), w, h, comp, buf) {
		return error('stbi_image failed to write bmp file to "${path}"')
	}
}

// stbi_write_png write on path a TGA file
pub fn stbi_write_tga(path string, w int, h int, comp int, buf &u8) ! {
	if 0 == C.stbi_write_tga(&char(path.str), w, h, comp, buf) {
		return error('stbi_image failed to write tga file to "${path}"')
	}
}

// stbi_write_png write on path a JPG file
// quality select the compression quality of the JPG
// quality is between 1 and 100. Higher quality looks better but results in a bigger image.
pub fn stbi_write_jpg(path string, w int, h int, comp int, buf &u8, quality int) ! {
	if 0 == C.stbi_write_jpg(&char(path.str), w, h, comp, buf, quality) {
		return error('stbi_image failed to write jpg file to "${path}"')
	}
}

/*
pub fn stbi_write_hdr(path string, w int, h int, comp int, buf &u8) ! {
	if 0 == C.stbi_write_hdr(&char(path.str), w , h , comp , buf){
		return error('stbi_image failed to write hdr file to "$path"')
	}
}
*/