vlib: add a TTF font loader and render in x.ttf (#7995)

.github/workflows/ci.yml

@@ -147,9 +147,15 @@ jobs:
       - name: Build V
         run: |
           make CC=clang
+      - name: Show PWD and Environment
+        run: |
+          echo "PWD:"
+          pwd
+          echo "ENVIRONMENT"
+          env
       - name: Test V fixed tests
         run: |
-          v -silent test-fixed
+          ./v -silent test-fixed
 
   macos:
     runs-on: macOS-latest

cmd/tools/modules/testing/common.v

@@ -122,13 +122,16 @@ pub fn new_test_session(_vargs string) TestSession {
 	}
 	if github_job != 'ubuntu-tcc' {
 		skip_files << 'examples/wkhtmltopdf.v' // needs installation of wkhtmltopdf from https://github.com/wkhtmltopdf/packaging/releases
+		// the ttf_test.v is not interactive, but needs X11 headers to be installed, which is done only on ubuntu-tcc for now
+		skip_files << 'vlib/x/ttf/ttf_test.v'
 	}
 	vargs := _vargs.replace('-progress', '').replace('-progress', '')
 	vexe := pref.vexe_path()
+	vroot := os.dir(vexe)
 	new_vtmp_dir := setup_new_vtmp_folder()
 	return TestSession{
 		vexe: vexe
-		vroot: os.dir(vexe)
+		vroot: vroot
 		skip_files: skip_files
 		vargs: vargs
 		vtmp_dir: new_vtmp_dir

examples/ttf_font/OFL.txt

@@ -0,0 +1,93 @@
+Copyright (c) 2012, Eduardo Tunni (http://www.tipo.net.ar), with Reserved Font Name "Imprima"
+
+This Font Software is licensed under the SIL Open Font License, Version 1.1.
+This license is copied below, and is also available with a FAQ at:
+http://scripts.sil.org/OFL
+
+
+-----------------------------------------------------------
+SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
+-----------------------------------------------------------
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded, 
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply
+to any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

examples/ttf_font/example_ttf.v

@@ -0,0 +1,202 @@
+import gg
+import gx
+import sokol.sapp
+import sokol.sgl
+
+import x.ttf
+import os
+//import math
+
+const (
+	win_width  = 600
+	win_height = 700
+	bg_color   = gx.white
+	font_paths = [
+		"Imprima-Regular.ttf"
+		"Graduate-Regular.ttf"
+	]
+)
+
+/******************************************************************************
+*
+* UI 
+*
+*****************************************************************************/
+struct App_data {
+pub mut:
+	gg        &gg.Context
+	sg_img    C.sg_image
+	init_flag bool
+	frame_c   int
+	
+	tf              []ttf.TTF_File
+	ttf_render      []ttf.TTF_render_Sokol
+	text_ready_flag bool
+	
+	mouse_x   int = -1
+	mouse_y   int = -1
+}
+
+fn my_init(mut app App_data) {
+	app.init_flag = true
+}
+
+fn draw_frame(mut app &App_data) {
+	cframe_txt := "Current Frame: $app.frame_c"
+	
+	app.gg.begin()
+
+	sgl.defaults()
+	sgl.matrix_mode_projection()
+	sgl.ortho(0.0, f32(sapp.width()), f32(sapp.height()), 0.0, -1.0, 1.0)
+	sgl.c4b(0, 0, 0, 255) // black
+
+	// draw a line as background
+	sgl.begin_line_strip()
+	sgl.v2f(10, 10)
+	sgl.v2f(100, 100)
+	sgl.end()
+
+	// draw text only if the app is already initialized
+	if app.init_flag == true {
+		sgl.begin_line_strip()
+		sgl.v2f(410, 400)
+		sgl.v2f(510, 400)
+		sgl.end()
+		
+		// update the text
+		mut txt1 := &app.ttf_render[0]
+		if app.frame_c % 2 == 0 {
+			txt1.destroy_texture()
+			txt1.create_text(cframe_txt ,43)
+			txt1.create_texture()
+		}
+ 
+		// ----- decomment if you want text rotation ----		
+		//txt1.bmp.angle = 3.141592 / 180 * f32(app.frame_c % 360)
+		//txt1.draw_text_bmp(app.gg, 300, 350)
+		//txt1.bmp.angle =  0
+		
+		txt1.draw_text_bmp(app.gg, 30, 60)
+
+		// block test
+		block_txt := "Today it is a good day!
+Tommorow I'm not so sure :(
+Frame: $app.frame_c
+But Vwill prevail for sure, V is the way!!
+òàèì@ò!£$%&
+"
+		txt1 = &app.ttf_render[1]
+		if app.frame_c % 2 == 0 {
+			
+			txt1.bmp.justify = false
+			if (app.frame_c>>6) % 2 == 0 {
+				//txt1.align = .left
+				txt1.bmp.justify = true
+			}
+			
+			txt1.bmp.align = .left
+			if (app.frame_c>>6) % 3 == 0 {
+				txt1.bmp.align = .right
+			}
+			txt1.destroy_texture()
+			txt1.create_text_block(block_txt, 500, 500, 32)
+			txt1.create_texture()
+		}
+		
+		// decomment if want block color change
+		//txt1.bmp.color = ttf.color_multiply(0xFF00FFFF, f32(app.frame_c % 255)/255.0)
+		
+		// decomment if want block rotation wanted
+		//txt1.bmp.angle = 3.141592/180 * f32(app.frame_c % 45)
+		
+		txt1.draw_text_bmp(app.gg, 30 + (app.frame_c>>1) & 0xFF , 200)
+		
+		// draw mouse position
+		if app.mouse_x >= 0 {
+			txt1 = &app.ttf_render[2]
+			txt1.destroy_texture()
+			txt1.create_text("$app.mouse_x,$app.mouse_y",25)
+			txt1.create_texture()
+			r := app.mouse_x % 255
+			g := app.mouse_y % 255
+			color := u32(r << 24) | u32(g << 16) | 0xFF
+			txt1.bmp.color = color
+			txt1.draw_text_bmp(app.gg, app.mouse_x , app.mouse_y)
+		}
+		
+		app.frame_c ++
+	}
+	
+	app.gg.end()
+}
+
+fn my_event_manager(mut ev sapp.Event, mut app &App_data) {
+	if ev.typ == .mouse_move {
+		app.mouse_x = int(ev.mouse_x)
+		app.mouse_y = int(ev.mouse_y)
+	}
+}
+
+[console]
+fn main(){
+    
+	mut app := &App_data{
+		gg: 0
+	}
+
+	app.gg = gg.new_context({
+		width: win_width
+		height: win_height
+		use_ortho: true // This is needed for 2D drawing
+		create_window: true
+		window_title: 'Test TTF module'
+		user_data: app
+		bg_color: bg_color
+		frame_fn: draw_frame
+		event_fn: my_event_manager
+		init_fn: my_init
+	})
+
+	// load TTF fonts
+	for font_path in font_paths {
+		mut tf := ttf.TTF_File{}
+		tf.buf = os.read_bytes(font_path) or { panic(err) }
+		println("TrueTypeFont file [$font_path] len: ${tf.buf.len}")
+		tf.init()
+		println("Unit per EM: $tf.units_per_em")
+		app.tf << tf
+	}
+	
+	// TTF render 0 Frame counter
+	app.ttf_render << &ttf.TTF_render_Sokol {
+		bmp: &ttf.BitMap{
+			tf: &(app.tf[0])
+			buf: malloc(32000000)
+			buf_size: (32000000)
+			color : 0xFF0000FF
+			//style: .raw
+			//use_font_metrics: true
+		}
+	}
+	
+	// TTF render 1 Text Block
+	app.ttf_render << &ttf.TTF_render_Sokol {
+		bmp: &ttf.BitMap{
+			tf: &(app.tf[1])
+			//color : 0xFF0000_10
+			//style: .raw
+			//use_font_metrics: true
+		}
+	}
+	
+	// TTF mouse position render
+	app.ttf_render << &ttf.TTF_render_Sokol {
+		bmp: &ttf.BitMap{
+			tf: &(app.tf[0])
+		}
+	}
+	
+	/* setup sokol_gfx */
+	app.gg.run()
+}

vlib/x/ttf/common.v

@@ -0,0 +1,184 @@
+module ttf
+/**********************************************************************
+*
+* Common data for the module
+*
+* Copyright (c) 2021 Dario Deledda. All rights reserved.
+* Use of this source code is governed by an MIT license
+* that can be found in the LICENSE file.
+*
+* Note:
+*
+* TODO: 
+**********************************************************************/
+import os
+import math
+
+// text align
+pub
+enum Text_align {
+	left
+	center
+	right
+	justify
+}
+
+// draw style
+pub
+enum Style {
+	outline
+	outline_aliased
+	filled
+	raw
+}
+
+/******************************************************************************
+*
+* DEBUG Utility
+*
+******************************************************************************/
+const debug_flag = false
+fn dprintln(txt string){
+	if debug_flag {
+		println(txt)
+	}
+}
+
+/******************************************************************************
+*
+* Utility
+*
+******************************************************************************/
+// write out a .ppm file
+pub
+fn (mut bmp BitMap) save_as_ppm(file_name string) {
+	npixels := bmp.width * bmp.height
+	mut f_out := os.create(file_name) or { panic(err) }
+	f_out.writeln('P3')
+	f_out.writeln('${bmp.width} ${bmp.height}')
+	f_out.writeln('255')
+	for i in 0..npixels {
+		pos := i * bmp.bp
+		unsafe {
+			c_r := 0xFF - bmp.buf[pos]
+			c_g := 0xFF - bmp.buf[pos +1 ]
+			c_b := 0xFF - bmp.buf[pos + 2]
+			f_out.write_str('${c_r} ${c_g} ${c_b} ')
+		}
+		
+	}
+	f_out.close()
+}
+
+pub
+fn (mut bmp BitMap) get_raw_bytes() []byte {
+	mut f_buf := []byte{len: bmp.buf_size/4}
+	mut i:=0
+	for i < bmp.buf_size {
+		unsafe { f_buf[i>>2] = *(bmp.buf + i) }
+		i += 4
+	}
+	return f_buf
+}
+
+pub
+fn (mut bmp BitMap) save_raw_data(file_name string) {
+	os.write_file_array(file_name, bmp.get_raw_bytes())
+}
+
+
+//
+// Math functions
+//
+[inline]
+fn abs(a int) int {
+	if a < 0 {
+		return -a
+	} else {
+		return a
+	}
+}
+
+[inline]
+fn fabs(a f32) f32 {
+	if a < 0 {
+		return -a
+	} else {
+		return a
+	}
+}
+
+// integer part of x
+[inline]
+fn ipart(x f32) f32 {
+    return f32(math.floor(x))
+}
+
+[inline]
+fn round(x f32) f32 {
+    return ipart(x + 0.5)
+}
+
+// fractional part of x
+[inline]
+fn fpart(x f32) f32 {
+    return x - f32(math.floor(x))
+}
+
+[inline]
+fn rfpart(x f32) f32 {
+    return 1 - fpart(x)
+}
+
+/******************************************************************************
+*
+* Colors
+*
+******************************************************************************/
+/*
+[inline]
+pub
+fn (mut dev BitMap) get_color(x int, y int) (int, int, int, int){
+	if x < 0 || x >= dev.width || y < 0 || y >= dev.height {
+		return 0,0,0,0
+	}
+	mut i := (x + y * dev.width)*dev.bp
+	unsafe{
+		return dev.buf[i], dev.buf[i+1], dev.buf[i+2], dev.buf[i+3]
+	}
+}
+
+[inline]
+pub
+fn (mut dev BitMap) get_color_u32(x int, y int) u32{
+	r, g, b, a := dev.get_color(x, y)
+	unsafe{
+		return u32(r<<24) | u32(g<<16) | u32(b<<8) | u32(a)
+	}
+}
+*/
+/******************************************************************************
+*
+* Drawing
+*
+******************************************************************************/
+[inline]
+pub 
+fn color_multiply_alpha(c u32, level f32) u32 {
+	return u32(f32( c & 0xFF) * level)
+}
+
+[inline]
+pub 
+fn color_multiply(c u32, level f32) u32 {
+	mut r := (f32((c >> 24) & 0xFF)/255.0) * level
+	mut g := (f32((c >> 16) & 0xFF)/255.0) * level
+	mut b := (f32((c >>  8) & 0xFF)/255.0) * level
+	mut a := (f32( c & 0xFF)/255.0)        * level
+	r = if r > 1.0 { 1.0 } else { r }
+	g = if g > 1.0 { 1.0 } else { g }
+	b = if b > 1.0 { 1.0 } else { b }
+	a = if a > 1.0 { 1.0 } else { a }
+
+	return (u32(r * 255) << 24) | (u32(g * 255) << 16) | (u32(b * 255) << 8) | u32(a * 255)
+}

vlib/x/ttf/render_bmp.v

@@ -0,0 +1,818 @@
+module ttf
+/**********************************************************************
+*
+* BMP render module utility functions
+*
+* Copyright (c) 2021 Dario Deledda. All rights reserved.
+* Use of this source code is governed by an MIT license
+* that can be found in the LICENSE file.
+*
+* Note:
+*
+* TODO: 
+* - manage text directions R to L 
+**********************************************************************/
+import encoding.utf8
+import math
+
+pub
+struct BitMap {
+pub mut:
+	tf     &TTF_File
+	
+	buf byteptr      // pointer to the memory buffer
+	buf_size int     // allocated buf size in bytes
+	
+	width  int  =1   // width of the buffer
+	height int  =1   // height of the buffer
+	bp     int  =4   // byte per pixel of the buffer
+	
+	bg_color u32     = 0xFFFFFF_00  // background RGBA format
+	color    u32     = 0x000000_FF  // RGBA format
+	scale    f32     = 1.0   // internal usage!!
+	scale_x  f32     = 1.0   // X scale of the single glyph
+	scale_y  f32     = 1.0   // Y scale of the single glyph
+	angle    f32     = 0.0   // angle of rotation of the bitmap
+	
+	// spaces
+	space_cw   f32   = 1.0   // width of the space glyph internal usage!!
+	space_mult f32   = f32(0.0) //1.0/16.0  // space between letter, is a multiplier for a standrd space ax
+	
+	// used only by internal text rendering!!
+	tr_matrix []f32  = [f32(1), 0, 0, 0, 1, 0, 0, 0, 0] // transformation matrix
+	ch_matrix []f32  = [f32(1), 0, 0, 0, 1, 0, 0, 0, 0] // character matrix
+
+	style              Style      = .filled // default syle
+	align              Text_align = .left   // default text align
+	justify            bool				    // justify text flag, default deactivated
+	justify_fill_ratio f32        = 0.5     // justify fill ratio, if the ratio of the filled row is >= of this then justify the text
+	
+	filler [][]int  // filler buffer for the renderer
+
+	// flag to force font embedded metrics
+	use_font_metrics bool 
+}
+
+/******************************************************************************
+*
+* Utility
+*
+******************************************************************************/
+// clear clear the bitmap with 0 bytes
+pub
+fn (mut bmp BitMap) clear() {
+	mut sz := bmp.width * bmp.height * bmp.bp
+	unsafe {
+		C.memset(bmp.buf, 0x00, sz)
+	}
+}
+
+// transform matrix applied to the text
+fn (bmp &BitMap) trf_txt(p &Point) (int, int) {
+	return int(p.x * bmp.tr_matrix[0] + p.y * bmp.tr_matrix[3] + bmp.tr_matrix[6]), 
+		   int(p.x * bmp.tr_matrix[1] + p.y * bmp.tr_matrix[4] + bmp.tr_matrix[7])
+}
+
+// transform matrix applied to the char
+fn (bmp &BitMap) trf_ch(p &Point) (int, int) {
+	return int(p.x * bmp.ch_matrix[0] + p.y * bmp.ch_matrix[3] + bmp.ch_matrix[6]), 
+		int(p.x * bmp.ch_matrix[1] + p.y * bmp.ch_matrix[4] + bmp.ch_matrix[7])
+}
+
+// set draw postion in the buffer
+pub 
+fn (mut bmp BitMap) set_pos(x f32, y f32) {
+		bmp.tr_matrix[6] = x
+		bmp.tr_matrix[7] = y
+}
+
+// set the rotation angle in radiants
+pub 
+fn (mut bmp BitMap) set_rotation(a f32) {
+	bmp.tr_matrix[0] = f32(math.cos(a))  //1
+	bmp.tr_matrix[1] = f32(-math.sin(a)) //0
+	bmp.tr_matrix[3] = f32(math.sin(a))  //0
+	bmp.tr_matrix[4] = f32(math.cos(a))  //1
+}
+
+/******************************************************************************
+*
+* Filler functions
+*
+******************************************************************************/
+pub
+fn (mut bmp BitMap) init_filler() {
+	h := bmp.height - bmp.filler.len 
+	if h < 1 {
+		return
+	}
+	for _ in 0..h {
+		bmp.filler << []int{len:4}
+	}
+	// dprintln("Init filler: ${bmp.filler.len} rows")
+}
+
+pub
+fn (mut bmp BitMap) clear_filler() {
+	for i in 0..bmp.height {
+		bmp.filler[i].clear()
+	}
+}
+
+pub
+fn (mut bmp BitMap) exec_filler() {
+	for y in 0..bmp.height {
+		if bmp.filler[y].len > 0 {
+			bmp.filler[y].sort()
+			if bmp.filler[y].len & 1 != 0 {
+				//dprintln("even line!! $y => ${bmp.filler[y]}")
+				continue
+			}
+			mut index := 0
+			for index < bmp.filler[y].len {
+				startx := bmp.filler[y][index] + 1
+				endx   := bmp.filler[y][index+1]
+				if startx >= endx { 
+					index += 2
+					continue 
+				}
+				for x in startx..endx {
+					bmp.plot(x, y, bmp.color)
+				}
+				index += 2
+			}
+		}
+	}
+}
+
+pub
+fn (mut bmp BitMap) fline(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32) {
+	mut x0 := f32(in_x0)
+	mut x1 := f32(in_x1)
+	mut y0 := f32(in_y0)
+	mut y1 := f32(in_y1)
+	mut tmp := f32(0)
+
+	// check bounds
+	if (in_x0 < 0 && in_x1 < 0) || (in_x0 > bmp.width && in_x1 > bmp.width) {
+		return
+	}
+
+	if y1 < y0 {
+		tmp = x0
+		x0 = x1
+		x1 = tmp
+
+		tmp = y0
+		y0 = y1
+		y1 = tmp
+	}
+
+	mut dx := x1 - x0
+	mut dy := y1 - y0
+	
+	if dy == 0 {
+		if in_y0 >= 0 && in_y0 < bmp.filler.len {
+			if in_x0 <= in_x1 {
+				bmp.filler[in_y0] << in_x0
+				bmp.filler[in_y0] << in_x1
+			} else {
+				bmp.filler[in_y0] << in_x1
+				bmp.filler[in_y0] << in_x0
+			}
+		}
+		return
+	}
+	mut n := dx / dy
+	for y in 0..int(dy+0.5) {
+		yd := int(y + y0)
+		x := n * y + x0
+		if x > bmp.width || yd >= bmp.filler.len { 
+			break 
+		}
+		if yd >= 0 && yd < bmp.filler.len {
+			bmp.filler[yd] << int(x+0.5)
+			//bmp.plot(int(x+0.5), yd, bmp.color)
+		}
+	}
+}
+
+/******************************************************************************
+*
+* Draw functions
+*
+******************************************************************************/
+[inline]
+pub
+fn (mut bmp BitMap) plot(x int, y int, c u32) bool {
+	if x < 0 || x >= bmp.width || y < 0 || y >= bmp.height {
+		return false
+	}
+	mut index := (x + y * bmp.width) * bmp.bp
+	unsafe {
+		//bmp.buf[index]=0xFF
+		bmp.buf[index] = byte(c & 0xFF) // write only the alpha
+	}
+/*	
+	for count in 0..(bmp.bp) {
+		unsafe{
+			bmp.buf[index + count] = byte((c >> (bmp.bp - count - 1) * 8) & 0x0000_00FF)
+		}
+	}
+*/
+	return true
+}
+
+/******************************************************************************
+*
+* smooth draw functions
+*
+******************************************************************************/
+// aline draw an aliased line on the bitmap
+pub
+fn (mut bmp BitMap) aline(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32) {
+	//mut c1 := c
+	mut x0 := f32(in_x0)
+	mut x1 := f32(in_x1)
+	mut y0 := f32(in_y0)
+	mut y1 := f32(in_y1)
+	mut tmp := f32(0)
+
+	mut dx := x1 - x0
+	mut dy := y1 - y0
+
+	dist := f32(0.4)
+
+	if fabs(dx) > fabs(dy) {
+		if x1 < x0 {
+			tmp = x0
+			x0 = x1
+			x1 = tmp
+
+			tmp = y0
+			y0 = y1
+			y1 = tmp
+		}
+		dx = x1 - x0
+		dy = y1 - y0
+
+		x0 += 0.5
+		y0 += 0.5
+
+		m := dy / dx
+		mut x := x0
+		for x <= x1 + 0.5 {
+			y := m * (x - x0) + y0
+			e := 1-fabs(y-0.5-int(y))
+			bmp.plot(int(x), int(y), color_multiply_alpha(c, e*0.75))
+			
+			ys1 := y + dist
+			if int(ys1) != int(y){
+				v1 := fabs(ys1 - y) / dist * (1 - e)
+				bmp.plot(int(x), int(ys1), color_multiply_alpha(c, v1))
+			}
+
+			ys2 := y - dist
+			if int(ys2) != int(y) {
+				v2 := fabs(y - ys2) / dist * (1 - e)
+				bmp.plot(int(x), int(ys2), color_multiply_alpha(c, v2))
+			}
+
+			x += 1.0
+		}
+		
+	} else {
+		if y1 < y0 {
+			tmp = x0
+			x0 = x1
+			x1 = tmp
+
+			tmp = y0
+			y0 = y1
+			y1 = tmp
+		}
+		dx = x1 - x0
+		dy = y1 - y0
+
+		x0 += 0.5
+		y0 += 0.5
+
+		n := dx / dy
+		mut y := y0
+		for y <= y1 + 0.5 {
+			x := n * (y - y0) + x0
+			e := f32(1 - fabs(x - 0.5 - int(x)))
+			bmp.plot(int(x), int(y), color_multiply_alpha(c, f32(e*0.75)))
+
+			xs1 := x + dist
+			if int(xs1) != int(x) {
+				v1 := fabs(xs1 - x) / dist * (1 - e)
+				bmp.plot(int(xs1), int(y), color_multiply_alpha(c, f32(v1)))
+			}
+
+			xs2 := x - dist
+			if int(xs2) != int(x) {
+				v2 := fabs(x - xs1) / dist * (1 - e)
+				bmp.plot(int(xs2), int(y), color_multiply_alpha(c, f32(v2)))
+			}
+			y += 1.0
+		}
+	}
+}
+
+/******************************************************************************
+*
+* draw functions
+*
+******************************************************************************/
+pub
+fn (mut bmp BitMap) line(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32) {
+	
+	// outline with aliased borders
+	if bmp.style == .outline_aliased {
+		bmp.aline(in_x0, in_y0, in_x1, in_y1, c)
+		return
+	}
+	// filled with aliased borders
+	else if bmp.style == .filled {
+		bmp.aline(in_x0, in_y0, in_x1, in_y1, c)
+		bmp.fline(in_x0, in_y0, in_x1, in_y1, c)
+		return
+	}
+	// only the filler is drawn
+	else if bmp.style == .raw {
+		bmp.fline(in_x0, in_y0, in_x1, in_y1, c)
+		return
+	}
+	// if we are here we are drawing an outlined border
+
+	x0 := int(in_x0)
+	x1 := int(in_x1)
+	y0 := int(in_y0)
+	y1 := int(in_y1)
+	//dprintln("line[$x0,$y0,$x1,$y1]")
+
+	mut x := x0
+	mut y := y0
+
+	dx := abs(x1 - x0)
+	sx := if x0 < x1 { 1 } else { -1 }
+	dy := -abs(y1 - y0)
+	sy := if y0 < y1 { 1 } else { -1 }
+	
+	// verical line
+	if dx == 0 {
+		if y0 < y1 {
+			for yt in y0..y1+1 {
+				bmp.plot(x0, yt, c)
+			}
+			return
+		}
+		for yt in y1..y0+1 {
+			bmp.plot(x0, yt, c)
+		}
+		return
+	// horizontal line
+	} else if dy == 0{
+		if x0 < x1 {
+			for xt in x0..x1+1 {
+				bmp.plot(xt, y0, c)
+			}
+			return
+		}
+		for xt in x1..x0+1 {
+			bmp.plot(xt, y0, c)
+		}
+		return
+	}
+
+	mut err := dx + dy // error value e_xy
+	for {
+		//bmp.plot(x, y, u32(0xFF00))
+		bmp.plot(x, y, c)
+	
+		//dprintln("$x $y [$x0,$y0,$x1,$y1]")
+		if x == x1 && y == y1 {
+			break
+		}
+		e2 := 2 * err
+		if e2 >= dy { // e_xy+e_x > 0
+			err += dy
+			x += sx
+		}
+		if e2 <= dx { // e_xy+e_y < 0
+			err += dx
+			y += sy
+		}
+	}
+
+}
+
+
+pub
+fn (mut bmp BitMap) box(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32) {
+	bmp.line(in_x0, in_y0, in_x1, in_y0, c)
+	bmp.line(in_x1, in_y0, in_x1, in_y1, c)
+	bmp.line(in_x0, in_y1, in_x1, in_y1, c)
+	bmp.line(in_x0, in_y0, in_x0, in_y1, c)
+}
+
+pub
+fn (mut bmp BitMap) quadratic(in_x0 int, in_y0 int, in_x1 int, in_y1 int, in_cx int, in_cy int, c u32) {
+	/*
+	x0 := int(in_x0 * bmp.scale)
+	x1 := int(in_x1 * bmp.scale)
+	y0 := int(in_y0 * bmp.scale)
+	y1 := int(in_y1 * bmp.scale)
+	cx := int(in_cx * bmp.scale)
+	cy := int(in_cy * bmp.scale)
+	*/
+	x0 := int(in_x0)
+	x1 := int(in_x1)
+	y0 := int(in_y0)
+	y1 := int(in_y1)
+	cx := int(in_cx)
+	cy := int(in_cy)
+
+	mut division := f64(1.0)
+	dx := abs(x0 - x1)
+	dy := abs(y0 - y1)
+	
+	// if few pixel draw a simple line
+	//if dx == 0 && dy == 0 {
+	if dx <= 2 || dy <= 2 {
+		//bmp.plot(x0, y0, c)
+		bmp.line(x0,y0,x1,y1, c)
+		return
+	}
+
+	division = 1.0/(f64( if dx>dy {dx} else {dy} ))
+	
+	//division = 0.1   // 10 division
+	//division = 0.25  // 4 division
+	
+	//dprintln("div: $division")
+	
+	/* 
+	----- Bezier quadratic form -----
+	t = 0.5; // given example value, half length of the curve
+	x = (1 - t) * (1 - t) * p[0].x + 2 * (1 - t) * t * p[1].x + t * t * p[2].x;
+	y = (1 - t) * (1 - t) * p[0].y + 2 * (1 - t) * t * p[1].y + t * t * p[2].y;
+	--------------------------------- 
+	*/
+
+	mut x_old := x0
+	mut y_old := y0
+	mut t := 0.0
+	
+	for t <= (1.0 + division/2.0){
+		s := 1.0 - t
+		x := s * s * x0 + 2.0 * s * t * cx + t * t * x1
+		y := s * s * y0 + 2.0 * s * t * cy + t * t * y1
+		xi := int(x + 0.5)
+		yi := int(y + 0.5)
+		//bmp.plot(xi, yi, c)
+		bmp.line(x_old, y_old, xi, yi, c)
+		x_old = xi
+		y_old = yi
+		t += division
+	}
+}
+
+/******************************************************************************
+*
+* TTF Query functions
+*
+******************************************************************************/
+pub 
+fn (mut bmp BitMap) get_chars_bbox(in_string string) []int {
+	mut res := []int{}
+	mut w := 0
+
+	mut space_cw, _ := bmp.tf.get_horizontal_metrics(u16(` `))
+	div_space_cw    := int((f32(space_cw) * bmp.space_mult) * bmp.scale)
+	space_cw        = int(space_cw * bmp.scale)
+
+	bmp.tf.reset_kern()
+
+	mut i := 0
+	for i < in_string.len {
+		mut char := u16(in_string[i])
+
+		// draw the space
+		if int(char) == 32 {
+			w += int(space_cw * bmp.space_cw)
+			i++
+			continue
+		}
+
+		// manage unicode chars like latin greek etc
+		c_len := ((0xe5000000>>((char>>3) & 0x1e)) & 3) + 1
+		if c_len > 1 {
+			tmp_char := utf8.get_uchar(in_string,i)
+			//dprintln("tmp_char: ${tmp_char.hex()}")
+			char = u16(tmp_char)
+		}
+		
+		c_index := bmp.tf.map_code(int(char))
+		ax , ay := bmp.tf.next_kern(c_index)
+		//dprintln("char_index: $c_index ax: $ax ay: $ay")
+
+		//cw, lsb := bmp.tf.get_horizontal_metrics(u16(char))
+		//dprintln("metrics: [${u16(char):c}] cw:$cw lsb:$lsb")
+		
+		//----- Calc Glyph transformations -----
+		mut x0 := w + int(ax * bmp.scale)
+		mut y0 := 0 + int(ay * bmp.scale)
+		
+		p := Point{x0,y0,false}
+		x1 , y1 := bmp.trf_txt(p)
+		// init ch_matrix
+		bmp.ch_matrix[0] = bmp.tr_matrix[0] * bmp.scale * bmp.scale_x
+		bmp.ch_matrix[1] = bmp.tr_matrix[1] * bmp.scale * bmp.scale_x
+		bmp.ch_matrix[3] = bmp.tr_matrix[3] * -bmp.scale * bmp.scale_y
+		bmp.ch_matrix[4] = bmp.tr_matrix[4] * -bmp.scale * bmp.scale_y
+		bmp.ch_matrix[6] = int(x1)
+		bmp.ch_matrix[7] = int(y1)
+
+		//x_min, x_max, y_min, y_max := bmp.tf.read_glyph_dim(c_index)
+		x_min, x_max, _, _ := bmp.tf.read_glyph_dim(c_index)
+		//-----------------
+
+		width := int( (abs(x_max + x_min) + ax) * bmp.scale)
+		//width := int((cw+ax) * bmp.scale)
+		w += width + div_space_cw
+		h := int(abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
+		res << w
+		res << h
+
+		i+= c_len
+	}
+  return res
+}
+
+pub 
+fn (mut bmp BitMap) get_bbox(in_string string) (int, int){
+	mut w := 0
+
+	mut space_cw, _ := bmp.tf.get_horizontal_metrics(u16(` `))
+	div_space_cw    := int((f32(space_cw) * bmp.space_mult) * bmp.scale)
+	space_cw        = int(space_cw * bmp.scale)
+
+	bmp.tf.reset_kern()
+
+	mut i := 0
+	for i < in_string.len {
+		mut char := u16(in_string[i])
+
+		// draw the space
+		if int(char) == 32 {
+			w += int(space_cw * bmp.space_cw)
+			i++
+			continue
+		}
+
+		// manage unicode chars like latin greek etc
+		c_len := ((0xe5000000>>((char>>3) & 0x1e)) & 3) + 1
+		if c_len > 1 {
+			tmp_char := utf8.get_uchar(in_string,i)
+			//dprintln("tmp_char: ${tmp_char.hex()}")
+			char = u16(tmp_char)
+		}
+		
+		c_index := bmp.tf.map_code(int(char))
+		ax , ay := bmp.tf.next_kern(c_index)
+		//dprintln("char_index: $c_index ax: $ax ay: $ay")
+
+		//cw, lsb := bmp.tf.get_horizontal_metrics(u16(char))
+		//dprintln("metrics: [${u16(char):c}] cw:$cw lsb:$lsb")
+		
+		//----- Calc Glyph transformations -----
+		mut x0 := w + int(ax * bmp.scale)
+		mut y0 := 0 + int(ay * bmp.scale)
+		
+		p := Point{x0,y0,false}
+		x1 , y1 := bmp.trf_txt(p)
+		// init ch_matrix
+		bmp.ch_matrix[0] = bmp.tr_matrix[0] * bmp.scale * bmp.scale_x
+		bmp.ch_matrix[1] = bmp.tr_matrix[1] * bmp.scale * bmp.scale_x
+		bmp.ch_matrix[3] = bmp.tr_matrix[3] * -bmp.scale * bmp.scale_y
+		bmp.ch_matrix[4] = bmp.tr_matrix[4] * -bmp.scale * bmp.scale_y
+		bmp.ch_matrix[6] = int(x1)
+		bmp.ch_matrix[7] = int(y1)
+
+		x_min, x_max, _, _ := bmp.tf.read_glyph_dim(c_index)
+		//x_min := 1
+		//x_max := 2
+		//-----------------
+
+		width := int( (abs(x_max + x_min) + ax) * bmp.scale)
+		//width := int((cw+ax) * bmp.scale)
+		w += width + div_space_cw
+
+		i+= c_len
+	}
+    
+	//dprintln("y_min: $bmp.tf.y_min y_max: $bmp.tf.y_max res: ${int((bmp.tf.y_max - bmp.tf.y_min)*buf.scale)} width: ${int( (cw) * buf.scale)}")
+	//buf.box(0,y_base - int((bmp.tf.y_min)*buf.scale), int( (x_max) * buf.scale), y_base-int((bmp.tf.y_max)*buf.scale), u32(0xFF00_0000) )
+	return w , int(abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
+}
+
+/******************************************************************************
+*
+* TTF draw glyph
+*
+******************************************************************************/
+pub
+fn (mut bmp BitMap) draw_text(in_string string) (int, int){
+	mut w := 0
+
+	mut space_cw, _ := bmp.tf.get_horizontal_metrics(u16(` `))
+	div_space_cw    := int((f32(space_cw) * bmp.space_mult) * bmp.scale)
+	space_cw        = int(space_cw * bmp.scale)
+
+	bmp.tf.reset_kern()
+
+	mut i := 0
+	for i < in_string.len {
+		mut char := u16(in_string[i])
+
+		// draw the space
+		if int(char) == 32 {
+			w += int(space_cw * bmp.space_cw)
+			i++
+			continue
+		}
+
+		// manage unicode chars like latin greek etc
+		c_len := ((0xe5000000>>((char>>3) & 0x1e)) & 3) + 1
+		if c_len > 1 {
+			tmp_char := utf8.get_uchar(in_string,i)
+			//dprintln("tmp_char: ${tmp_char.hex()}")
+			char = u16(tmp_char)
+		}
+		
+	    c_index := bmp.tf.map_code(int(char))
+	    ax , ay := bmp.tf.next_kern(c_index)
+	    //dprintln("char_index: $c_index ax: $ax ay: $ay")
+
+	    cw, _ := bmp.tf.get_horizontal_metrics(u16(char))
+			//cw, lsb := bmp.tf.get_horizontal_metrics(u16(char))
+	    //dprintln("metrics: [${u16(char):c}] cw:$cw lsb:$lsb")
+	    
+	    //----- Draw_Glyph transformations -----
+	    mut x0 := w + int(ax * bmp.scale)
+	    mut y0 := 0 + int(ay * bmp.scale)
+	    
+			p := Point{x0,y0,false}
+	    x1 , y1 := bmp.trf_txt(p)
+	    // init ch_matrix
+	    bmp.ch_matrix[0] = bmp.tr_matrix[0] * bmp.scale * bmp.scale_x
+	    bmp.ch_matrix[1] = bmp.tr_matrix[1] * bmp.scale * bmp.scale_x
+	    bmp.ch_matrix[3] = bmp.tr_matrix[3] * -bmp.scale * bmp.scale_y
+	    bmp.ch_matrix[4] = bmp.tr_matrix[4] * -bmp.scale * bmp.scale_y
+	    bmp.ch_matrix[6] = int(x1)
+	    bmp.ch_matrix[7] = int(y1)
+
+	    x_min, x_max := bmp.draw_glyph(c_index)
+	    // x_min := 1
+			// x_max := 2
+			//-----------------
+
+			mut width := int( (abs(x_max + x_min) + ax) * bmp.scale)
+			if bmp.use_font_metrics {
+				width = int((cw+ax) * bmp.scale)
+	    }
+			w += width + div_space_cw
+
+	    i+= c_len
+    }
+    
+    //dprintln("y_min: $bmp.tf.y_min y_max: $bmp.tf.y_max res: ${int((bmp.tf.y_max - bmp.tf.y_min)*buf.scale)} width: ${int( (cw) * buf.scale)}")
+    //buf.box(0,y_base - int((bmp.tf.y_min)*buf.scale), int( (x_max) * buf.scale), y_base-int((bmp.tf.y_max)*buf.scale), u32(0xFF00_0000) )
+    return w , int(abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
+}
+
+pub
+fn (mut bmp BitMap) draw_glyph(index u16) (int, int){
+	glyph := bmp.tf.read_glyph(index)
+	
+	if !glyph.valid_glyph {
+		return 0, 0
+	}
+
+	if bmp.style == .filled || bmp.style == .raw {
+		bmp.clear_filler()
+	}
+
+	mut s             := 0  // status
+	mut c             := 0  // contours count
+	mut contour_start := 0
+	mut x0            := 0
+	mut y0            := 0
+	color             := bmp.color //u32(0xFFFF_FF00) // RGBA white
+	//color1            := u32(0xFF00_0000) // RGBA red
+	//color2            := u32(0x00FF_0000) // RGBA green
+
+	mut sp_x := 0
+	mut sp_y := 0
+	mut point := Point{}
+
+	for count, point_raw in glyph.points {
+		//dprintln("count: $count, state: $s pl:$glyph.points.len")
+		point.x = point_raw.x
+		point.y = point_raw.y
+		
+		point.x , point.y = bmp.trf_ch(point)
+		point.on_curve = point_raw.on_curve
+		
+		if s == 0 {
+			x0 = point.x
+			y0 = point.y
+			sp_x = x0
+			sp_y = y0
+			s = 1 // next state
+			continue
+		} else if s == 1 {
+			if point.on_curve {
+				bmp.line(x0, y0, point.x, point.y, color)
+				//bmp.aline(x0, y0, point.x, point.y, u32(0xFFFF0000))
+				x0 = point.x
+				y0 = point.y
+			} else {
+				s = 2
+			}
+			
+		} else {
+			//dprintln("s==2")
+			mut prev := glyph.points[count - 1]
+			prev.x, prev.y = bmp.trf_ch(prev)
+			if point.on_curve {
+				//dprintln("HERE1")
+				// ctx.quadraticCurveTo(prev.x + x, prev.y + y,point.x + x, point.y + y);
+				//bmp.line(x0, y0, point.x + in_x, point.y + in_y, color1)
+				//bmp.quadratic(x0, y0, point.x + in_x, point.y + in_y, prev.x + in_x, prev.y + in_y, u32(0xa0a00000))
+				bmp.quadratic(x0, y0, point.x, point.y, prev.x, prev.y, color)
+				x0 = point.x
+				y0 = point.y
+				s = 1
+			} else {
+				//dprintln("HERE2")
+				// ctx.quadraticCurveTo(prev.x + x, prev.y + y,
+	            //            (prev.x + point.x) / 2 + x,
+	            //            (prev.y + point.y) / 2 + y);
+	            
+	            //bmp.line(x0, y0, (prev.x + point.x)/2, (prev.y + point.y)/2, color2)
+	            //bmp.quadratic(x0, y0, (prev.x + point.x)/2, (prev.y + point.y)/2, prev.x, prev.y, color2)
+	            bmp.quadratic(x0, y0, (prev.x + point.x)/2, (prev.y + point.y)/2, prev.x, prev.y, color)
+	            x0 = (prev.x + point.x)/2
+				y0 = (prev.y + point.y)/2
+			}
+		}
+		
+		if count == glyph.contour_ends[c] {
+			//dprintln("count == glyph.contour_ends[count]")
+			if s == 2 { // final point was off-curve. connect to start
+				
+                mut start_point := glyph.points[contour_start]
+                start_point.x, start_point.y = bmp.trf_ch(start_point)
+                if point.on_curve {
+					//ctx.quadraticCurveTo(prev.x + x, prev.y + y,
+                    //        point.x + x, point.y + y);
+			//bmp.line(x0, y0, start_point.x + in_x, start_point.y + in_y, u32(0x00FF0000))
+			
+			bmp.quadratic(x0, y0, start_point.x, start_point.y , 
+			//	start_point.x + in_x, start_point.y + in_y, u32(0xFF00FF00))
+				start_point.x, start_point.y, color)            
+				} else {
+					//ctx.quadraticCurveTo(prev.x + x, prev.y + y,
+                    //        (prev.x + point.x) / 2 + x,
+                    //        (prev.y + point.y) / 2 + y);
+                    
+                    //bmp.line(x0, y0, start_point.x, start_point.y, u32(0x00FF0000)
+                    bmp.quadratic(x0, y0, start_point.x, start_point.y, 
+			(point.x + start_point.x)/2,
+			(point.y + start_point.y)/2,
+			//u32(0xFF000000))              
+						color)
+				}
+			}else{
+				// last point not in a curve
+				//bmp.line(point.x, point.y, sp_x, sp_y, u32(0x00FF0000))
+				bmp.line(point.x, point.y, sp_x, sp_y, color)
+			}
+			contour_start = count + 1
+			s = 0
+			c++
+		}
+	}
+
+	if bmp.style == .filled || bmp.style == .raw {
+		bmp.exec_filler()
+	}
+	x_min := glyph.x_min
+	x_max := glyph.x_max
+	return x_min, x_max
+	
+	//return glyph.x_min, glyph.x_max
+}

vlib/x/ttf/render_sokol_cpu.v

@@ -0,0 +1,234 @@
+module ttf
+/**********************************************************************
+*
+* BMP render module utility functions
+*
+* Copyright (c) 2021 Dario Deledda. All rights reserved.
+* Use of this source code is governed by an MIT license
+* that can be found in the LICENSE file.
+*
+* Note:
+*
+* TODO: 
+**********************************************************************/
+import math
+import gg
+import sokol.sgl
+
+pub
+struct TTF_render_Sokol {
+pub mut:
+	bmp &BitMap // Base bitmap render
+	
+	// rendering fields
+	sg_img C.sg_image // sokol image
+	scale_reduct f32  = 2.0 // scale of the cpu texture for filtering
+	device_dpi   int  = 72  // device DPI
+}
+
+/******************************************************************************
+*
+* Render functions
+*
+******************************************************************************/
+fn (mut tf_skl TTF_render_Sokol) format_texture(){
+	r := byte(tf_skl.bmp.color >> 24)
+	g := byte((tf_skl.bmp.color >> 16) & 0xFF)
+	b := byte((tf_skl.bmp.color >> 8 ) & 0xFF)
+	a := byte(tf_skl.bmp.color & 0xFF)
+
+	b_r := byte(tf_skl.bmp.bg_color >> 24)
+	b_g := byte((tf_skl.bmp.bg_color >> 16) & 0xFF)
+	b_b := byte((tf_skl.bmp.bg_color >> 8 ) & 0xFF)
+	b_a := byte(tf_skl.bmp.bg_color & 0xFF)
+	
+	// trasform buffer in a texture
+	x := byteptr(tf_skl.bmp.buf)
+	unsafe{
+		mut i := 0
+		for i<tf_skl.bmp.buf_size {
+			data := x[i]
+			if data > 0 {			
+				x[i+0] = r
+				x[i+1] = g
+				x[i+2] = b
+				// alpha
+				x[i+3] = byte((a * data) >> 8)
+			} else {
+				x[i+0] = b_r
+				x[i+1] = b_g
+				x[i+2] = b_b
+				x[i+3] = b_a
+			}
+			i += 4
+		}
+	}
+}
+
+pub
+fn (mut tf_skl TTF_render_Sokol) create_text(in_txt string, in_font_size f32){
+	scale_reduct := tf_skl.scale_reduct
+	device_dpi := tf_skl.device_dpi
+	font_size := in_font_size //* scale_reduct
+	
+	// Formula: (font_size * device dpi) / (72dpi * em_unit)
+	//scale := ((1.0  * devide_dpi )/ f32(72 * tf_skl.bmp.tf.units_per_em))* font_size
+	scale := f32(font_size * device_dpi) / f32(72 * tf_skl.bmp.tf.units_per_em)
+	//dprintln("Scale: $scale")
+		
+	tf_skl.bmp.scale =  scale * scale_reduct
+	w, h := tf_skl.bmp.get_bbox(in_txt)
+	tf_skl.bmp.width  = int(w)
+	tf_skl.bmp.height = int((h+8))
+	sz := tf_skl.bmp.width * tf_skl.bmp.height * tf_skl.bmp.bp
+	
+	// RAM buffer
+	if sz > tf_skl.bmp.buf_size {
+		if sz > 0 {
+			free(tf_skl.bmp.buf)
+		}
+		dprintln("create_text Alloc: $sz bytes")
+		tf_skl.bmp.buf = malloc(sz)
+		tf_skl.bmp.buf_size = sz
+	}
+
+	tf_skl.bmp.init_filler()
+	
+	// draw the text
+	mut y_base := int((tf_skl.bmp.tf.y_max - tf_skl.bmp.tf.y_min) * tf_skl.bmp.scale)
+	tf_skl.bmp.set_pos(0,y_base)
+	tf_skl.bmp.clear()
+	tf_skl.bmp.draw_text(in_txt)
+	tf_skl.format_texture()
+}
+
+pub
+fn (mut tf_skl TTF_render_Sokol) create_text_block(in_txt string, in_w int, in_h int, in_font_size f32){
+	scale_reduct := tf_skl.scale_reduct
+	device_dpi := tf_skl.device_dpi
+	font_size := in_font_size //* scale_reduct
+	// Formula: (font_size * device dpi) / (72dpi * em_unit)
+	//scale := ((1.0  * devide_dpi )/ f32(72 * tf_skl.bmp.tf.units_per_em))* font_size
+	scale := f32(font_size * device_dpi) / f32(72 * tf_skl.bmp.tf.units_per_em)
+	//dprintln("Scale: $scale")
+		
+	tf_skl.bmp.scale =  scale * scale_reduct
+	w := in_w
+	h := in_h
+	tf_skl.bmp.width  = int(w * scale_reduct + 0.5)
+	tf_skl.bmp.height = int((h+2) * scale_reduct + 0.5)
+	sz := tf_skl.bmp.width * tf_skl.bmp.height * tf_skl.bmp.bp
+		
+	//if true { return }
+	
+	// RAM buffer
+	if sz > tf_skl.bmp.buf_size {
+		if sz > 0 {
+			free(tf_skl.bmp.buf)
+		}
+		dprintln("Alloc: $sz bytes")
+		tf_skl.bmp.buf = malloc(sz)
+		tf_skl.bmp.buf_size = sz
+	}
+
+	tf_skl.bmp.init_filler()
+	
+	// draw the text
+	mut y_base := int((tf_skl.bmp.tf.y_max - tf_skl.bmp.tf.y_min) * tf_skl.bmp.scale)
+	tf_skl.bmp.set_pos(0,y_base)
+	tf_skl.bmp.clear()
+	
+	tf_skl.bmp.draw_text_block(in_txt, {x: 0, y:0, w:w, h:h})
+	tf_skl.format_texture()
+}
+/******************************************************************************
+*
+* Sokol Render functions
+*
+******************************************************************************/
+pub
+fn (mut tf_skl TTF_render_Sokol) create_texture(){
+	w := tf_skl.bmp.width
+	h := tf_skl.bmp.height
+	sz := tf_skl.bmp.width * tf_skl.bmp.height * tf_skl.bmp.bp
+	mut img_desc := C.sg_image_desc{
+		width: w
+		height: h
+		num_mipmaps: 0
+		min_filter:   .linear
+    mag_filter:   .linear
+		//usage: .dynamic
+		wrap_u: .clamp_to_edge
+		wrap_v: .clamp_to_edge
+		label: &byte(0)
+		d3d11_texture: 0
+	}
+	// comment for dynamic
+	img_desc.content.subimage[0][0] = C.sg_subimage_content{
+		ptr: tf_skl.bmp.buf
+		size: sz
+	}
+	
+	simg := C.sg_make_image(&img_desc)
+	//free(tf_skl.bmp.buf)  // DONT FREE IF Dynamic
+	tf_skl.sg_img = simg
+}
+
+pub
+fn (tf_skl TTF_render_Sokol) destroy_texture(){
+	C.sg_destroy_image(tf_skl.sg_img)
+}
+
+// Use only if usage: .dynamic
+pub
+fn (mut tf_skl TTF_render_Sokol) update_text_texture(){
+	sz := tf_skl.bmp.width * tf_skl.bmp.height * tf_skl.bmp.bp
+	mut tmp_sbc := C.sg_image_content{}
+	tmp_sbc.subimage[0][0] = C.sg_subimage_content {
+		ptr: tf_skl.bmp.buf
+		size: sz
+	}
+	C.sg_update_image(tf_skl.sg_img, &tmp_sbc)
+}
+
+pub
+fn (tf_skl TTF_render_Sokol) draw_text_bmp(ctx &gg.Context, x f32, y f32) {
+	//width  := tf_skl.bmp.width  >> 1
+	//height := tf_skl.bmp.height >> 1
+	sgl.push_matrix()
+	
+	width  := tf_skl.bmp.width  / (tf_skl.scale_reduct)
+	height := tf_skl.bmp.height / (tf_skl.scale_reduct)
+	
+	u0 := f32(0.0)
+	v0 := f32(0.0)
+	u1 := f32(1.0)
+	v1 := f32(1.0)
+	x0 := f32(0)
+	y0 := f32(0)
+	x1 := f32(width) * ctx.scale
+	y1 := f32(height) * ctx.scale
+
+	ca := f32(math.cos(tf_skl.bmp.angle))
+	sa := f32(math.sin(tf_skl.bmp.angle))
+	m := [
+		f32(ca),-sa,0,0,
+		sa,ca,0,0,
+		0,0,1,0,
+		x,y,0,1
+	]
+	sgl.mult_matrix(m)
+	//
+	sgl.load_pipeline(ctx.timage_pip)
+	sgl.enable_texture()
+	sgl.texture(tf_skl.sg_img)
+	sgl.begin_quads()
+	sgl.c4b(255, 255, 255, 255)
+	sgl.v2f_t2f(x0, y0, u0, v0)
+	sgl.v2f_t2f(x1, y0, u1, v0)
+	sgl.v2f_t2f(x1, y1, u1, v1)
+	sgl.v2f_t2f(x0, y1, u0, v1)
+	sgl.end()
+	sgl.disable_texture()
+	sgl.pop_matrix()
+}

vlib/x/ttf/text_block.v

@@ -0,0 +1,122 @@
+module ttf
+/**********************************************************************
+*
+* BMP render module utility functions
+*
+* Copyright (c) 2021 Dario Deledda. All rights reserved.
+* Use of this source code is governed by an MIT license
+* that can be found in the LICENSE file.
+*
+* Note:
+*
+* TODO: 
+**********************************************************************/
+pub 
+struct Text_block {
+	x int
+	y int
+	w int // width of the text block
+	h int // heigth of the text block
+	cut_lines bool = true
+}
+
+
+fn (mut dev BitMap) get_justify_space_cw(txt string, w int, block_w int, space_cw int) f32 {
+	num_spaces := txt.count(" ")
+	if num_spaces < 1 {
+		return 0
+	}
+	delta := block_w - w
+	//println("num spc: $num_spaces")
+	//println("delta: ${txt} w:$w bw:$block_w space_cw:$space_cw")
+	res := f32(delta)/f32(num_spaces)/f32(space_cw)
+	//println("res: $res")
+	return res
+}
+
+// write out a text
+pub
+fn (mut bmp BitMap) draw_text_block(text string, block Text_block) {
+	mut x := block.x
+	mut y := block.y
+	mut y_base := int((bmp.tf.y_max - bmp.tf.y_min) * bmp.scale)
+
+	//bmp.box(x, y, x + block.w, y + block.h, u32(0xFF00_0000))
+
+	// spaces data
+	mut space_cw, _ := bmp.tf.get_horizontal_metrics(u16(` `))
+	space_cw        = int(space_cw * bmp.scale)
+
+	old_space_cw := bmp.space_cw
+
+	mut offset_flag := f32(0) // default .left align
+	if bmp.align == .right {
+		offset_flag = 1
+	} else if bmp.align == .center {
+		offset_flag = 0.5
+	}
+
+	for txt in text.split_into_lines() {
+		bmp.space_cw = old_space_cw
+		mut w,mut h := bmp.get_bbox(txt)
+		if w <= block.w || block.cut_lines == false {
+			//println("Solid block!")
+			left_offset := int((block.w - w) * offset_flag)
+			if bmp.justify && (f32(w) / f32(block.w)) >=  bmp.justify_fill_ratio {
+				bmp.space_cw = old_space_cw + bmp.get_justify_space_cw(txt, w, block.w, space_cw)
+			}
+			bmp.set_pos(x + left_offset ,y + y_base)
+			bmp.draw_text(txt)
+			//---- DEBUG ----
+			//mut txt_w , mut txt_h := bmp.draw_text(txt)
+			//bmp.box(x + left_offset,y+y_base - int((bmp.tf.y_min)*bmp.scale), x + txt_w + left_offset, y + y_base - int((bmp.tf.y_max) * bmp.scale), u32(0x00ff_0000) )
+			//---------------
+			y += y_base
+		} else {
+			//println("to cut: ${txt}")
+			mut txt1 := txt.split(" ")
+			mut c:= txt1.len
+			//mut done := false
+			for c > 0 {
+				tmp_str := txt1[0..c].join(' ')
+				//println("tmp_str: ${tmp_str}")
+				if tmp_str.len < 1 {
+					break
+				}
+				
+				bmp.space_cw = old_space_cw
+				w,h = bmp.get_bbox(tmp_str)
+				if w <= block.w {
+					mut left_offset := int((block.w - w) * offset_flag)
+					if bmp.justify && (f32(w) / f32(block.w)) >=  bmp.justify_fill_ratio {
+						//println("cut phase!")
+						bmp.space_cw = 0.0
+						w,h = bmp.get_bbox(tmp_str)
+						left_offset = int((block.w - w) * offset_flag)
+						bmp.space_cw = bmp.get_justify_space_cw(tmp_str, w, block.w, space_cw)
+					} else {
+						bmp.space_cw = old_space_cw
+					}
+					bmp.set_pos(x + left_offset, y + y_base)
+					bmp.draw_text(tmp_str)
+					//---- DEBUG ----
+					//txt_w , txt_h := bmp.draw_text(tmp_str)
+					//println("printing [${x},${y}] => '${tmp_str}' space_cw: $bmp.space_cw")
+					//bmp.box(x + left_offset,y + y_base - int((bmp.tf.y_min)*bmp.scale), x + txt_w + left_offset, y + y_base - int((bmp.tf.y_max) * bmp.scale), u32(0x00ff_0000) )
+					//---------------
+					y += y_base
+					txt1 = txt1[c..]
+					c= txt1.len
+					//---- DEBUG ----
+					//txt2 := txt1.join(' ')
+					//println("new string: ${txt2} len: ${c}")
+					//---------------
+				} else {
+					c--
+				}
+			}
+		}
+	}
+
+	bmp.space_cw = old_space_cw
+}