From a67d49050c52efda62585e4e9be134d8d43d7b24 Mon Sep 17 00:00:00 2001
From: Lukas Neubert <serkonda@protonmail.com>
Date: Fri, 12 Mar 2021 10:28:04 +0100
Subject: [PATCH] math: add a pure V `math.mathutil`, with generic `min`, `max`
 and `abs` functions (#9176), and use it consistently

---
 examples/2048/2048.v               | 48 ++++-------------
 vlib/gg/gg.v                       | 12 ++---
 vlib/gg/m4/m4_test.v               |  2 +-
 vlib/math/mathutil/mathutil.v      | 31 +++++++++++
 vlib/math/mathutil/mathutil_test.v | 22 ++++++++
 vlib/math/util/util.v              | 82 ++++++++++++++++++++++++++++++
 vlib/term/ui/ui.v                  |  6 ---
 vlib/v/doc/utils.v                 |  7 +--
 vlib/v/fmt/fmt.v                   |  3 +-
 vlib/v/fmt/struct.v                | 11 ++--
 vlib/v/scanner/scanner.v           |  3 +-
 vlib/v/util/errors.v               | 15 +++---
 vlib/v/util/util.v                 | 15 ------
 vlib/x/ttf/common.v                | 18 -------
 vlib/x/ttf/render_bmp.v            | 43 ++++++++--------
 15 files changed, 193 insertions(+), 125 deletions(-)
 create mode 100644 vlib/math/mathutil/mathutil.v
 create mode 100644 vlib/math/mathutil/mathutil_test.v
 create mode 100644 vlib/math/util/util.v

diff --git a/examples/2048/2048.v b/examples/2048/2048.v
index 1c6c47765f..4f57bb30cd 100644
--- a/examples/2048/2048.v
+++ b/examples/2048/2048.v
@@ -1,6 +1,7 @@
 import gg
 import gx
 import math
+import math.mathutil as mu
 import os
 import rand
 import time
@@ -200,33 +201,6 @@ enum Direction {
 }
 
 // Utility functions
-[inline]
-fn min(a int, b int) int {
-	if a < b {
-		return a
-	} else {
-		return b
-	}
-}
-
-[inline]
-fn max(a int, b int) int {
-	if a > b {
-		return a
-	} else {
-		return b
-	}
-}
-
-[inline]
-fn abs(a int) int {
-	if a < 0 {
-		return -a
-	} else {
-		return a
-	}
-}
-
 [inline]
 fn avg(a int, b int) int {
 	return (a + b) / 2
@@ -591,7 +565,7 @@ fn (mut app App) resize() {
 	window_size := gg.window_size()
 	w := window_size.width
 	h := window_size.height
-	m := f32(min(w, h))
+	m := f32(mu.min(w, h))
 	app.ui.dpi_scale = s
 	app.ui.window_width = w
 	app.ui.window_height = h
@@ -615,7 +589,7 @@ fn (app &App) draw() {
 	xpad, ypad := app.ui.x_padding, app.ui.y_padding
 	ww := app.ui.window_width
 	wh := app.ui.window_height
-	m := min(ww, wh)
+	m := mu.min(ww, wh)
 	labelx := xpad + app.ui.border_size
 	labely := ypad + app.ui.border_size / 2
 	app.draw_tiles()
@@ -649,7 +623,7 @@ fn (app &App) draw_tiles() {
 	xstart := app.ui.x_padding + app.ui.border_size
 	ystart := app.ui.y_padding + app.ui.border_size + app.ui.header_size
 	toffset := app.ui.tile_size + app.ui.padding_size
-	tiles_size := min(app.ui.window_width, app.ui.window_height) - app.ui.border_size * 2
+	tiles_size := mu.min(app.ui.window_width, app.ui.window_height) - app.ui.border_size * 2
 	// Draw the padding around the tiles
 	app.gg.draw_rounded_rect(xstart, ystart, tiles_size / 2, tiles_size / 2, tiles_size / 24,
 		app.theme.padding_color)
@@ -711,8 +685,8 @@ fn (app &App) draw_tiles() {
 
 fn (mut app App) handle_touches() {
 	s, e := app.touch.start, app.touch.end
-	adx, ady := abs(e.pos.x - s.pos.x), abs(e.pos.y - s.pos.y)
-	if max(adx, ady) < 10 {
+	adx, ady := mu.abs(e.pos.x - s.pos.x), mu.abs(e.pos.y - s.pos.y)
+	if mu.max(adx, ady) < 10 {
 		app.handle_tap()
 	} else {
 		app.handle_swipe()
@@ -722,7 +696,7 @@ fn (mut app App) handle_touches() {
 fn (mut app App) handle_tap() {
 	_, ypad := app.ui.x_padding, app.ui.y_padding
 	w, h := app.ui.window_width, app.ui.window_height
-	m := min(w, h)
+	m := mu.min(w, h)
 	s, e := app.touch.start, app.touch.end
 	avgx, avgy := avg(s.pos.x, e.pos.x), avg(s.pos.y, e.pos.y)
 	// TODO: Replace "touch spots" with actual buttons
@@ -760,12 +734,12 @@ fn (mut app App) handle_swipe() {
 	s, e := app.touch.start, app.touch.end
 	w, h := app.ui.window_width, app.ui.window_height
 	dx, dy := e.pos.x - s.pos.x, e.pos.y - s.pos.y
-	adx, ady := abs(dx), abs(dy)
-	dmin := if min(adx, ady) > 0 { min(adx, ady) } else { 1 }
-	dmax := if max(adx, ady) > 0 { max(adx, ady) } else { 1 }
+	adx, ady := mu.abs(dx), mu.abs(dy)
+	dmin := if mu.min(adx, ady) > 0 { mu.min(adx, ady) } else { 1 }
+	dmax := if mu.max(adx, ady) > 0 { mu.max(adx, ady) } else { 1 }
 	tdiff := int(e.time.unix_time_milli() - s.time.unix_time_milli())
 	// TODO: make this calculation more accurate (don't use arbitrary numbers)
-	min_swipe_distance := int(math.sqrt(min(w, h) * tdiff / 100)) + 20
+	min_swipe_distance := int(math.sqrt(mu.min(w, h) * tdiff / 100)) + 20
 	if dmax < min_swipe_distance {
 		return
 	}
diff --git a/vlib/gg/gg.v b/vlib/gg/gg.v
index 532f7da5e6..e6c55bb85b 100644
--- a/vlib/gg/gg.v
+++ b/vlib/gg/gg.v
@@ -9,6 +9,7 @@ import sokol.sapp
 import sokol.sgl
 import sokol.gfx
 import math
+import math.mathutil as mu
 
 // import time
 pub type FNCb = fn (x voidptr)
@@ -538,13 +539,6 @@ pub fn (gg &Context) end() {
 	*/
 }
 
-fn abs(a f32) f32 {
-	if a >= 0 {
-		return a
-	}
-	return -a
-}
-
 pub fn (mut ctx Context) resize(width int, height int) {
 	ctx.width = width
 	ctx.height = height
@@ -556,8 +550,8 @@ pub fn (ctx &Context) draw_line(x f32, y f32, x2 f32, y2 f32, c gx.Color) {
 	}
 	if ctx.scale > 1 {
 		// Make the line more clear on hi dpi screens: draw a rectangle
-		mut width := abs(x2 - x)
-		mut height := abs(y2 - y)
+		mut width := mu.abs(x2 - x)
+		mut height := mu.abs(y2 - y)
 		if width == 0 {
 			width = 1
 		} else if height == 0 {
diff --git a/vlib/gg/m4/m4_test.v b/vlib/gg/m4/m4_test.v
index c92a74ffbc..90b46407e0 100644
--- a/vlib/gg/m4/m4_test.v
+++ b/vlib/gg/m4/m4_test.v
@@ -232,4 +232,4 @@ fn test_proj() {
 	assert m4.mul_vec(ort, m4.Vec4{[ f32(150),	100,	0, 1]!}) == m4.Vec4{[ f32(0),	0,	0, 1]!}
 	assert m4.mul_vec(ort, m4.Vec4{[ f32(0),	0,	0, 1]!}) == m4.Vec4{[ f32(-1),	-1,	0, 1]!}
 	assert m4.mul_vec(ort, m4.Vec4{[ f32(300),	200,	0, 1]!}) == m4.Vec4{[ f32(1),	1,	0, 1]!}
-}
\ No newline at end of file
+}
diff --git a/vlib/math/mathutil/mathutil.v b/vlib/math/mathutil/mathutil.v
new file mode 100644
index 0000000000..9ebb991983
--- /dev/null
+++ b/vlib/math/mathutil/mathutil.v
@@ -0,0 +1,31 @@
+// Copyright (c) 2019-2021 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 mathutil
+
+[inline]
+pub fn min<T>(a T, b T) T {
+	if a < b {
+		return a
+	} else {
+		return b
+	}
+}
+
+[inline]
+pub fn max<T>(a T, b T) T {
+	if a > b {
+		return a
+	} else {
+		return b
+	}
+}
+
+[inline]
+pub fn abs<T>(a T) T {
+	if a > 0 {
+		return a
+	} else {
+		return -a
+	}
+}
diff --git a/vlib/math/mathutil/mathutil_test.v b/vlib/math/mathutil/mathutil_test.v
new file mode 100644
index 0000000000..6b3b68ac0a
--- /dev/null
+++ b/vlib/math/mathutil/mathutil_test.v
@@ -0,0 +1,22 @@
+import math.mathutil as mu
+
+fn test_min() {
+	assert mu.min(42, 13) == 13
+	assert mu.min(5, -10) == -10
+	assert mu.min(7.1, 7.3) == 7.1
+	assert mu.min(u32(32), u32(17)) == 17
+}
+
+fn test_max() {
+	assert mu.max(42, 13) == 42
+	assert mu.max(5, -10) == 5
+	assert mu.max(7.1, 7.3) == 7.3
+	assert mu.max(u32(60), u32(17)) == 60
+}
+
+fn test_abs() {
+	assert mu.abs(99) == 99
+	assert mu.abs(-10) == 10
+	assert mu.abs(1.2345) == 1.2345
+	assert mu.abs(-5.5) == 5.5
+}
diff --git a/vlib/math/util/util.v b/vlib/math/util/util.v
new file mode 100644
index 0000000000..0802d2843d
--- /dev/null
+++ b/vlib/math/util/util.v
@@ -0,0 +1,82 @@
+// Copyright (c) 2019-2021 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 util
+
+// imin returns the smallest of two integer values
+[inline]
+pub fn imin(a int, b int) int {
+	return if a < b { a } else { b }
+}
+
+// imin returns the biggest of two integer values
+[inline]
+pub fn imax(a int, b int) int {
+	return if a > b { a } else { b }
+}
+
+// iabs returns an integer as absolute value
+[inline]
+pub fn iabs(v int) int {
+	return if v > 0 { v } else { -v }
+}
+
+// umin returns the smallest of two u32 values
+[inline]
+pub fn umin(a u32, b u32) u32 {
+	return if a < b { a } else { b }
+}
+
+// umax returns the biggest of two u32 values
+[inline]
+pub fn umax(a u32, b u32) u32 {
+	return if a > b { a } else { b }
+}
+
+// uabs returns an u32 as absolute value
+[inline]
+pub fn uabs(v u32) u32 {
+	return if v > 0 { v } else { -v }
+}
+
+// fmin_32 returns the smallest `f32` of input `a` and `b`.
+// Example: assert fmin_32(2.0,3.0) == 2.0
+[inline]
+pub fn fmin_32(a f32, b f32) f32 {
+	return if a < b { a } else { b }
+}
+
+// fmax_32 returns the largest `f32` of input `a` and `b`.
+// Example: assert fmax_32(2.0,3.0) == 3.0
+[inline]
+pub fn fmax_32(a f32, b f32) f32 {
+	return if a > b { a } else { b }
+}
+
+// fabs_32 returns the absolute value of `a` as a `f32` value.
+// Example: assert fabs_32(-2.0) == 2.0
+[inline]
+pub fn fabs_32(v f32) f32 {
+	return if v > 0 { v } else { -v }
+}
+
+// fmin_64 returns the smallest `f64` of input `a` and `b`.
+// Example: assert fmin_64(2.0,3.0) == 2.0
+[inline]
+pub fn fmin_64(a f64, b f64) f64 {
+	return if a < b { a } else { b }
+}
+
+// fmax_64 returns the largest `f64` of input `a` and `b`.
+// Example: assert fmax_64(2.0,3.0) == 3.0
+[inline]
+pub fn fmax_64(a f64, b f64) f64 {
+	return if a > b { a } else { b }
+}
+
+// fabs_64 returns the absolute value of `a` as a `f64` value.
+// Example: assert fabs_64(-2.0) == f64(2.0)
+[inline]
+pub fn fabs_64(v f64) f64 {
+	return if v > 0 { v } else { -v }
+}
diff --git a/vlib/term/ui/ui.v b/vlib/term/ui/ui.v
index 1d8ed694f4..70279adb1f 100644
--- a/vlib/term/ui/ui.v
+++ b/vlib/term/ui/ui.v
@@ -254,9 +254,3 @@ pub fn (mut ctx Context) horizontal_separator(y int) {
 	ctx.set_cursor_position(0, y)
 	ctx.write(strings.repeat(/* `⎽` */`-`, ctx.window_width))
 }
-
-
-[inline]
-fn abs(a int) int {
-	return if a < 0 { -a } else { a }
-}
diff --git a/vlib/v/doc/utils.v b/vlib/v/doc/utils.v
index c721e51f52..b5559f2a26 100644
--- a/vlib/v/doc/utils.v
+++ b/vlib/v/doc/utils.v
@@ -1,5 +1,6 @@
 module doc
 
+import math.mathutil as mu
 import strings
 import v.ast
 import v.util
@@ -93,11 +94,11 @@ fn (mut d Doc) convert_pos(filename string, pos token.Position) DocPos {
 		d.sources[filename] = util.read_file(os.join_path(d.base_path, filename)) or { '' }
 	}
 	source := d.sources[filename]
-	mut p := util.imax(0, util.imin(source.len - 1, pos.pos))
-	column := util.imax(0, pos.pos - p - 1)
+	mut p := mu.max(0, mu.min(source.len - 1, pos.pos))
+	column := mu.max(0, pos.pos - p - 1)
 	return DocPos{
 		line: pos.line_nr + 1
-		col: util.imax(1, column + 1)
+		col: mu.max(1, column + 1)
 		len: pos.len
 	}
 }
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 66ff8f0c1c..b3ea72d487 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -3,6 +3,7 @@
 // that can be found in the LICENSE file.
 module fmt
 
+import math.mathutil as mu
 import v.ast
 import v.table
 import strings
@@ -70,7 +71,7 @@ pub fn fmt(file ast.File, table &table.Table, pref &pref.Preferences, is_debug b
 	if res.len == 1 {
 		return f.out_imports.str().trim_space() + '\n'
 	}
-	bounded_import_pos := util.imin(res.len, f.import_pos)
+	bounded_import_pos := mu.min(res.len, f.import_pos)
 	return res[..bounded_import_pos] + f.out_imports.str() + res[bounded_import_pos..]
 }
 
diff --git a/vlib/v/fmt/struct.v b/vlib/v/fmt/struct.v
index db73ece5c8..4fe03efde1 100644
--- a/vlib/v/fmt/struct.v
+++ b/vlib/v/fmt/struct.v
@@ -3,9 +3,9 @@
 // that can be found in the LICENSE file.
 module fmt
 
+import math.mathutil as mu
 import strings
 import v.ast
-import v.util
 
 const (
 	threshold_to_align_struct = 8
@@ -75,8 +75,7 @@ fn (mut list []CommentAndExprAlignInfo) add_info(attrs_len int, type_len int, li
 		list.add_new_info(attrs_len, type_len, line)
 		return
 	}
-	d_len := util.iabs(list[i].max_attrs_len - attrs_len) +
-		util.iabs(list[i].max_type_len - type_len)
+	d_len := mu.abs(list[i].max_attrs_len - attrs_len) + mu.abs(list[i].max_type_len - type_len)
 	if !(d_len < fmt.threshold_to_align_struct) {
 		list.add_new_info(attrs_len, type_len, line)
 		return
@@ -167,15 +166,15 @@ pub fn (mut f Fmt) struct_decl(node ast.StructDecl) {
 			// keep one empty line between fields (exclude one after mut:, pub:, ...)
 			mut before_last_line := node.fields[i - 1].pos.line_nr
 			if node.fields[i - 1].comments.len > 0 {
-				before_last_line = util.imax(before_last_line, node.fields[i - 1].comments.last().pos.last_line)
+				before_last_line = mu.max(before_last_line, node.fields[i - 1].comments.last().pos.last_line)
 			}
 			if node.fields[i - 1].has_default_expr {
-				before_last_line = util.imax(before_last_line, node.fields[i - 1].default_expr.position().last_line)
+				before_last_line = mu.max(before_last_line, node.fields[i - 1].default_expr.position().last_line)
 			}
 
 			mut next_first_line := field.pos.line_nr
 			if field.comments.len > 0 {
-				next_first_line = util.imin(next_first_line, field.comments[0].pos.line_nr)
+				next_first_line = mu.min(next_first_line, field.comments[0].pos.line_nr)
 			}
 			if next_first_line - before_last_line > 1 {
 				f.writeln('')
diff --git a/vlib/v/scanner/scanner.v b/vlib/v/scanner/scanner.v
index e568969222..f265ba8bee 100644
--- a/vlib/v/scanner/scanner.v
+++ b/vlib/v/scanner/scanner.v
@@ -3,6 +3,7 @@
 // that can be found in the LICENSE file.
 module scanner
 
+import math.mathutil as mu
 import os
 import v.token
 import v.pref
@@ -1057,7 +1058,7 @@ fn (mut s Scanner) text_scan() token.Token {
 
 fn (mut s Scanner) invalid_character() {
 	len := utf8_char_len(s.text[s.pos])
-	end := util.imin(s.pos + len, s.text.len)
+	end := mu.min(s.pos + len, s.text.len)
 	c := s.text[s.pos..end]
 	s.error('invalid character `$c`')
 }
diff --git a/vlib/v/util/errors.v b/vlib/v/util/errors.v
index ee86fd6383..21790c0ebb 100644
--- a/vlib/v/util/errors.v
+++ b/vlib/v/util/errors.v
@@ -3,6 +3,7 @@
 // that can be found in the LICENSE file.
 module util
 
+import math.mathutil as mu
 import os
 import strings
 import term
@@ -81,7 +82,7 @@ pub fn formatted_error(kind string, omsg string, filepath string, pos token.Posi
 	}
 	//
 	source, column := filepath_pos_to_source_and_column(filepath, pos)
-	position := '$path:${pos.line_nr + 1}:${imax(1, column + 1)}:'
+	position := '$path:${pos.line_nr + 1}:${mu.max(1, column + 1)}:'
 	scontext := source_context(kind, source, column, pos).join('\n')
 	final_position := bold(position)
 	final_kind := bold(color(kind, kind))
@@ -95,7 +96,7 @@ pub fn filepath_pos_to_source_and_column(filepath string, pos token.Position) (s
 	// TODO: optimize this; may be use a cache.
 	// The column should not be so computationally hard to get.
 	source := read_file(filepath) or { '' }
-	mut p := imax(0, imin(source.len - 1, pos.pos))
+	mut p := mu.max(0, mu.min(source.len - 1, pos.pos))
 	if source.len > 0 {
 		for ; p >= 0; p-- {
 			if source[p] == `\n` || source[p] == `\r` {
@@ -103,7 +104,7 @@ pub fn filepath_pos_to_source_and_column(filepath string, pos token.Position) (s
 			}
 		}
 	}
-	column := imax(0, pos.pos - p - 1)
+	column := mu.max(0, pos.pos - p - 1)
 	return source, column
 }
 
@@ -113,13 +114,13 @@ pub fn source_context(kind string, source string, column int, pos token.Position
 		return clines
 	}
 	source_lines := source.split_into_lines()
-	bline := imax(0, pos.line_nr - util.error_context_before)
-	aline := imax(0, imin(source_lines.len - 1, pos.line_nr + util.error_context_after))
+	bline := mu.max(0, pos.line_nr - util.error_context_before)
+	aline := mu.max(0, mu.min(source_lines.len - 1, pos.line_nr + util.error_context_after))
 	tab_spaces := '    '
 	for iline := bline; iline <= aline; iline++ {
 		sline := source_lines[iline]
-		start_column := imax(0, imin(column, sline.len))
-		end_column := imax(0, imin(column + imax(0, pos.len), sline.len))
+		start_column := mu.max(0, mu.min(column, sline.len))
+		end_column := mu.max(0, mu.min(column + mu.max(0, pos.len), sline.len))
 		cline := if iline == pos.line_nr {
 			sline[..start_column] + color(kind, sline[start_column..end_column]) +
 				sline[end_column..]
diff --git a/vlib/v/util/util.v b/vlib/v/util/util.v
index d6eb9de456..897bb6d2b7 100644
--- a/vlib/v/util/util.v
+++ b/vlib/v/util/util.v
@@ -372,21 +372,6 @@ pub fn skip_bom(file_content string) string {
 	return raw_text
 }
 
-[inline]
-pub fn imin(a int, b int) int {
-	return if a < b { a } else { b }
-}
-
-[inline]
-pub fn imax(a int, b int) int {
-	return if a > b { a } else { b }
-}
-
-[inline]
-pub fn iabs(v int) int {
-	return if v > 0 { v } else { -v }
-}
-
 pub fn replace_op(s string) string {
 	if s.len == 1 {
 		last_char := s[s.len - 1]
diff --git a/vlib/x/ttf/common.v b/vlib/x/ttf/common.v
index 370c333d04..e0d1160625 100644
--- a/vlib/x/ttf/common.v
+++ b/vlib/x/ttf/common.v
@@ -133,24 +133,6 @@ pub fn (mut bmp BitMap) save_raw_data(file_name string) {
 //
 // 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 {
diff --git a/vlib/x/ttf/render_bmp.v b/vlib/x/ttf/render_bmp.v
index 6802b59d27..ef854df469 100644
--- a/vlib/x/ttf/render_bmp.v
+++ b/vlib/x/ttf/render_bmp.v
@@ -10,11 +10,12 @@ module ttf
 *
 * Note:
 *
-* TODO: 
-* - manage text directions R to L 
+* TODO:
+* - manage text directions R to L
 **********************************************************************/
 import encoding.utf8
 import math
+import math.mathutil as mu
 
 pub struct BitMap {
 pub mut:
@@ -226,7 +227,7 @@ pub fn (mut bmp BitMap) aline(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32)
 
 	dist := f32(0.4)
 
-	if fabs(dx) > fabs(dy) {
+	if mu.abs(dx) > mu.abs(dy) {
 		if x1 < x0 {
 			tmp = x0
 			x0 = x1
@@ -246,18 +247,18 @@ pub fn (mut bmp BitMap) aline(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32)
 		mut x := x0
 		for x <= x1 + 0.5 {
 			y := m * (x - x0) + y0
-			e := 1 - fabs(y - 0.5 - int(y))
+			e := 1 - mu.abs(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)
+				v1 := mu.abs(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)
+				v2 := mu.abs(y - ys2) / dist * (1 - e)
 				bmp.plot(int(x), int(ys2), color_multiply_alpha(c, v2))
 			}
 
@@ -283,18 +284,18 @@ pub fn (mut bmp BitMap) aline(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32)
 		mut y := y0
 		for y <= y1 + 0.5 {
 			x := n * (y - y0) + x0
-			e := f32(1 - fabs(x - 0.5 - int(x)))
+			e := f32(1 - mu.abs(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)
+				v1 := mu.abs(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)
+				v2 := mu.abs(x - xs1) / dist * (1 - e)
 				bmp.plot(int(xs2), int(y), color_multiply_alpha(c, f32(v2)))
 			}
 			y += 1.0
@@ -335,9 +336,9 @@ pub fn (mut bmp BitMap) line(in_x0 int, in_y0 int, in_x1 int, in_y1 int, c u32)
 	mut x := x0
 	mut y := y0
 
-	dx := abs(x1 - x0)
+	dx := mu.abs(x1 - x0)
 	sx := if x0 < x1 { 1 } else { -1 }
-	dy := -abs(y1 - y0)
+	dy := -mu.abs(y1 - y0)
 	sy := if y0 < y1 { 1 } else { -1 }
 
 	// verical line
@@ -411,8 +412,8 @@ pub fn (mut bmp BitMap) quadratic(in_x0 int, in_y0 int, in_x1 int, in_y1 int, in
 	cy := int(in_cy)
 
 	mut division := f64(1.0)
-	dx := abs(x0 - x1)
-	dy := abs(y0 - y1)
+	dx := mu.abs(x0 - x1)
+	dy := mu.abs(y0 - y1)
 
 	// if few pixel draw a simple line
 	// if dx == 0 && dy == 0 {
@@ -520,10 +521,10 @@ pub fn (mut bmp BitMap) get_chars_bbox(in_string string) []int {
 		x_min, x_max, _, _ := bmp.tf.read_glyph_dim(c_index)
 		//-----------------
 
-		width := int((abs(x_max + x_min) + ax) * bmp.scale)
+		width := int((mu.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)
+		h := int(mu.abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
 		res << w
 		res << h
 
@@ -591,7 +592,7 @@ pub fn (mut bmp BitMap) get_bbox(in_string string) (int, int) {
 		// x_max := 2
 		//-----------------
 
-		width := int((abs(x_max + x_min) + ax) * bmp.scale)
+		width := int((mu.abs(x_max + x_min) + ax) * bmp.scale)
 		// width := int((cw+ax) * bmp.scale)
 		w += width + div_space_cw
 
@@ -600,7 +601,7 @@ pub fn (mut bmp BitMap) get_bbox(in_string string) (int, int) {
 
 	// 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)
+	return w, int(mu.abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
 }
 
 /******************************************************************************
@@ -620,7 +621,7 @@ fn (mut bmp BitMap) draw_notdef_glyph(in_x int, in_w int) {
 	bmp.ch_matrix[7] = int(y1)
 	x, y := bmp.trf_ch(p)
 
-	y_h := fabs(bmp.tf.y_max - bmp.tf.y_min) * bmp.scale * 0.5
+	y_h := mu.abs(bmp.tf.y_max - bmp.tf.y_min) * bmp.scale * 0.5
 
 	bmp.box(int(x), int(y), int(x - in_w), int(y - y_h), bmp.color)
 	bmp.line(int(x), int(y), int(x - in_w), int(y - y_h), bmp.color)
@@ -689,7 +690,7 @@ pub fn (mut bmp BitMap) draw_text(in_string string) (int, int) {
 		// x_max := 2
 		//-----------------
 
-		mut width := int((abs(x_max + x_min) + ax) * bmp.scale)
+		mut width := int((mu.abs(x_max + x_min) + ax) * bmp.scale)
 		if bmp.use_font_metrics {
 			width = int((cw + ax) * bmp.scale)
 		}
@@ -699,7 +700,7 @@ pub fn (mut bmp BitMap) draw_text(in_string string) (int, int) {
 
 	// 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)
+	return w, int(mu.abs(int(bmp.tf.y_max - bmp.tf.y_min)) * bmp.scale)
 }
 
 pub fn (mut bmp BitMap) draw_glyph(index u16) (int, int) {
@@ -798,7 +799,7 @@ pub fn (mut bmp BitMap) draw_glyph(index u16) (int, int) {
 					//        (prev.y + point.y) / 2 + y);
 
 					// bmp.line(x0, y0, start_point.x, start_point.y, u32(0x00FF0000)
-					// u32(0xFF000000))              
+					// u32(0xFF000000))
 					bmp.quadratic(x0, y0, start_point.x, start_point.y, (point.x +
 						start_point.x) / 2, (point.y + start_point.y) / 2, color)
 				}