stbi: add image writing functions (#12754)

thirdparty/stb_image/stb_image.h

@@ -561,6 +561,7 @@ STBIDEF int   stbi_zlib_decode_noheader_buffer(char *obuffer, int olen, const ch
 #include <string.h>
 #include <limits.h>
 
+
 #if !defined(STBI_NO_LINEAR) || !defined(STBI_NO_HDR)
 #include <math.h>  // ldexp, pow
 #endif

thirdparty/stb_image/stb_v_header.h

@@ -0,0 +1,6 @@
+/*
+* stbi set globals var functions
+*/
+void set_png_compression_level(int level);
+void write_force_png_filter(int level);
+void write_tga_with_rle(int level);

thirdparty/stb_image/stbi.c

@@ -1,3 +1,22 @@
-
 #define STB_IMAGE_IMPLEMENTATION
+#define STB_IMAGE_WRITE_IMPLEMENTATION
 #include "stb_image.h"
+#include "stb_image_write.h"
+
+/*
+void set_png_compression_level(int level);
+void write_force_png_filter(int level);
+void write_tga_with_rle(int level);
+*/
+
+void set_png_compression_level(int level) {
+	stbi_write_png_compression_level = level;
+}
+
+void write_force_png_filter(int level){
+	stbi_write_force_png_filter = level;
+}
+
+void write_tga_with_rle(int level) {
+	stbi_write_tga_with_rle = level;
+}

vlib/stbi/stbi.c.v

@@ -6,6 +6,8 @@ module stbi
 
 #flag -I @VEXEROOT/thirdparty/stb_image
 #include "stb_image.h"
+#include "stb_image_write.h"
+#include "stb_v_header.h"
 #flag @VEXEROOT/thirdparty/stb_image/stbi.o
 
 pub struct Image {
@@ -18,20 +20,71 @@ pub mut:
 	ext         string
 }
 
-fn C.stbi_load(filename &char, x &int, y &int, channels_in_file &int, desired_channels int) &byte
-
-fn C.stbi_load_from_file(f voidptr, x &int, y &int, channels_in_file &int, desired_channels int) &byte
-
-fn C.stbi_load_from_memory(buffer &byte, len int, x &int, y &int, channels_in_file &int, desired_channels int) &byte
-
-fn C.stbi_image_free(retval_from_stbi_load &byte)
-
+//-----------------------------------------------------------------------------
+//
+// 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)
 
-fn init() {
-	set_flip_vertically_on_load(false)
+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 &byte)
+
+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) &byte
+fn C.stbi_load_from_file(f voidptr, x &int, y &int, channels_in_file &int, desired_channels int) &byte
+fn C.stbi_load_from_memory(buffer &byte, len int, x &int, y &int, channels_in_file &int, desired_channels int) &byte
+
+// load load an image from a path
 pub fn load(path string) ?Image {
 	ext := path.all_after_last('.')
 	mut res := Image{
@@ -48,11 +101,12 @@ pub fn load(path string) ?Image {
 		res.nr_channels = 4
 	}
 	if isnil(res.data) {
-		return error('stbi image failed to load from "$path"')
+		return error('stbi_image failed to load from "$path"')
 	}
 	return res
 }
 
+// load_from_memory load an image from a memory buffer
 pub fn load_from_memory(buf &byte, bufsize int) ?Image {
 	mut res := Image{
 		ok: true
@@ -62,26 +116,58 @@ pub fn load_from_memory(buf &byte, bufsize int) ?Image {
 	res.data = C.stbi_load_from_memory(buf, bufsize, &res.width, &res.height, &res.nr_channels,
 		flag)
 	if isnil(res.data) {
-		return error('stbi image failed to load from memory')
+		return error('stbi_image failed to load from memory')
 	}
 	return res
 }
 
-pub fn (img &Image) free() {
-	C.stbi_image_free(img.data)
+//-----------------------------------------------------------------------------
+//
+// Write functions
+//
+//-----------------------------------------------------------------------------
+fn C.stbi_write_png(filename &char, w int, h int, comp int, buffer &byte, stride_in_bytes int) int
+fn C.stbi_write_bmp(filename &char, w int, h int, comp int, buffer &byte) int
+fn C.stbi_write_tga(filename &char, w int, h int, comp int, buffer &byte) int
+fn C.stbi_write_jpg(filename &char, w int, h int, comp int, buffer &byte, quality int) int
+
+// fn C.stbi_write_hdr(filename &char, w int, h int, comp int, buffer &byte) int // buffer &byte => 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 &byte, 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 "$path"')
+	}
+}
+
+// stbi_write_png write on path a BMP file
+pub fn stbi_write_bmp(path string, w int, h int, comp int, buf &byte) ? {
+	if 0 == C.stbi_write_bmp(&char(path.str), w, h, comp, buf) {
+		return error('stbi_image failed to write bmp file to "$path"')
+	}
+}
+
+// stbi_write_png write on path a TGA file
+pub fn stbi_write_tga(path string, w int, h int, comp int, buf &byte) ? {
+	if 0 == C.stbi_write_tga(&char(path.str), w, h, comp, buf) {
+		return error('stbi_image failed to write tga file to "$path"')
+	}
+}
+
+// stbi_write_png write on path a JPG file
+// quality select teh compression quality of the JPG
+// quality is between 1 and 100. Higher quality looks better but results in a bigger image.
+pub fn stbi_write_jpg(path string, w int, h int, comp int, buf &byte, quality int) ? {
+	if 0 == C.stbi_write_jpg(&char(path.str), w, h, comp, buf, quality) {
+		return error('stbi_image failed to write jpg file to "$path"')
+	}
 }
 
 /*
-pub fn (img Image) tex_image_2d() {
-	mut rgb_flag := C.GL_RGB
-	if img.ext == 'png' {
-		rgb_flag = C.GL_RGBA
+pub fn stbi_write_hdr(path string, w int, h int, comp int, buf &byte) ? {
+	if 0 == C.stbi_write_hdr(&char(path.str), w , h , comp , buf){
+		return error('stbi_image failed to write hdr file to "$path"')
 	}
-	C.glTexImage2D(C.GL_TEXTURE_2D, 0, rgb_flag, img.width, img.height, 0,
-		rgb_flag, C.GL_UNSIGNED_BYTE,	img.data)
 }
 */
-
-pub fn set_flip_vertically_on_load(val bool) {
-	C.stbi_set_flip_vertically_on_load(val)
-}

vlib/stbi/stbi_test.v

@@ -0,0 +1,34 @@
+import os
+import stbi
+
+fn test_stbi_read_write() {
+	vroot := @VEXEROOT
+	path := os.join_path(vroot, 'examples', 'assets', 'logo.png')
+	println('Source path: $path')
+	d_s := stbi.load(path) or { panic(err) }
+	println('Image source data:\n $d_s')
+
+	out_path := os.join_path(os.temp_dir(), 'test.png')
+	println('Out path: $out_path')
+	stbi.stbi_write_png(out_path, d_s.width, d_s.height, 4, d_s.data, d_s.width * 4) or {
+		panic(err)
+	}
+
+	d_d := stbi.load(out_path) or { panic(err) }
+	println('Image dest data:\n $d_d')
+
+	assert d_s.width == d_d.width
+	assert d_s.height == d_d.height
+	assert d_s.nr_channels == d_d.nr_channels
+
+	mut v_s := &u32(d_s.data)
+	mut v_d := &u32(d_d.data)
+	mut delta := i64(0)
+	for index in 0 .. (d_d.width * d_d.width) {
+		unsafe {
+			delta += v_s[index] - v_d[index]
+		}
+	}
+	assert 0 == delta
+	os.rm(out_path) or {}
+}