mirror of
https://github.com/Ed94/VEFontCache-Odin.git
synced 2025-08-06 06:52:44 -07:00
496 lines
14 KiB
Odin
496 lines
14 KiB
Odin
package VEFontCache
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/*
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Notes:
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Freetype will do memory allocations and has an interface the user can implement.
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That interface is not exposed from this parser but could be added to parser_init.
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STB_Truetype has macros for its allocation unfortuantely
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*/
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import "base:runtime"
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import "core:c"
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import "core:math"
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import stbtt "vendor:stb/truetype"
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import freetype "thirdparty:freetype"
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ParserKind :: enum u32 {
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STB_TrueType,
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Freetype,
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}
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ParserFontInfo :: struct {
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label : string,
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kind : ParserKind,
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using _ : struct #raw_union {
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stbtt_info : stbtt.fontinfo,
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freetype_info : freetype.Face
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},
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data : []byte,
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}
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GlyphVertType :: enum u8 {
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None,
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Move = 1,
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Line,
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Curve,
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Cubic,
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}
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// Based directly off of stb_truetype's vertex
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ParserGlyphVertex :: struct {
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x, y : i16,
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contour_x0, contour_y0 : i16,
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contour_x1, contour_y1 : i16,
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type : GlyphVertType,
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padding : u8,
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}
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// A shape can be a dynamic array free_type or an opaque set of data handled by stb_truetype
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ParserGlyphShape :: [dynamic]ParserGlyphVertex
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ParserContext :: struct {
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kind : ParserKind,
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ft_library : freetype.Library,
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// fonts : HMapChained(ParserFontInfo),
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}
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parser_init :: proc( ctx : ^ParserContext )
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{
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switch ctx.kind
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{
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case .Freetype:
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result := freetype.init_free_type( & ctx.ft_library )
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assert( result == freetype.Error.Ok, "VEFontCache.parser_init: Failed to initialize freetype" )
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case .STB_TrueType:
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// Do nothing intentional
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}
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// error : AllocatorError
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// ctx.fonts, error = make( HMapChained(ParserFontInfo), 256 )
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// assert( error == .None, "VEFontCache.parser_init: Failed to allocate fonts array" )
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}
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parser_shutdown :: proc( ctx : ^ParserContext )
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{
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// TODO(Ed): Implement
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}
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parser_load_font :: proc( ctx : ^ParserContext, label : string, data : []byte ) -> (font : ParserFontInfo)
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{
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// key := font_key_from_label(label)
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// font = get( ctx.fonts, key )
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// if font != nil do return
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// error : AllocatorError
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// font, error = set( ctx.fonts, key, ParserFontInfo {} )
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// assert( error == .None, "VEFontCache.parser_load_font: Failed to set a new parser font info" )
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switch ctx.kind
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{
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case .Freetype:
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error := freetype.new_memory_face( ctx.ft_library, raw_data(data), cast(i32) len(data), 0, & font.freetype_info )
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if error != .Ok do return
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case .STB_TrueType:
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success := stbtt.InitFont( & font.stbtt_info, raw_data(data), 0 )
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if ! success do return
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}
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font.label = label
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font.data = data
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return
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}
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parser_unload_font :: proc( font : ^ParserFontInfo )
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{
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switch font.kind {
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case .Freetype:
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error := freetype.done_face( font.freetype_info )
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assert( error == .Ok, "VEFontCache.parser_unload_font: Failed to unload freetype face" )
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case .STB_TrueType:
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// Do Nothing
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}
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}
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parser_find_glyph_index :: #force_inline proc "contextless" ( font : ^ParserFontInfo, codepoint : rune ) -> (glyph_index : Glyph)
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{
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switch font.kind
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{
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case .Freetype:
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glyph_index = transmute(Glyph) freetype.get_char_index( font.freetype_info, transmute(u32) codepoint )
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return
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case .STB_TrueType:
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glyph_index = transmute(Glyph) stbtt.FindGlyphIndex( & font.stbtt_info, codepoint )
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return
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}
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return Glyph(-1)
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}
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parser_free_shape :: proc( font : ^ParserFontInfo, shape : ParserGlyphShape )
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{
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switch font.kind
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{
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case .Freetype:
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delete(shape)
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case .STB_TrueType:
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stbtt.FreeShape( & font.stbtt_info, transmute( [^]stbtt.vertex) raw_data(shape) )
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}
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}
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parser_get_codepoint_horizontal_metrics :: #force_inline proc "contextless" ( font : ^ParserFontInfo, codepoint : rune ) -> ( advance, to_left_side_glyph : i32 )
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{
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switch font.kind
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{
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case .Freetype:
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glyph_index := transmute(Glyph) freetype.get_char_index( font.freetype_info, transmute(u32) codepoint )
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if glyph_index != 0
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{
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freetype.load_glyph( font.freetype_info, c.uint(codepoint), { .No_Bitmap, .No_Hinting, .No_Scale } )
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advance = i32(font.freetype_info.glyph.advance.x) >> 6
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to_left_side_glyph = i32(font.freetype_info.glyph.metrics.hori_bearing_x) >> 6
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}
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else
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{
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advance = 0
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to_left_side_glyph = 0
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}
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case .STB_TrueType:
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stbtt.GetCodepointHMetrics( & font.stbtt_info, codepoint, & advance, & to_left_side_glyph )
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}
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return
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}
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parser_get_codepoint_kern_advance :: #force_inline proc "contextless" ( font : ^ParserFontInfo, prev_codepoint, codepoint : rune ) -> i32
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{
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switch font.kind
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{
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case .Freetype:
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prev_glyph_index := transmute(Glyph) freetype.get_char_index( font.freetype_info, transmute(u32) prev_codepoint )
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glyph_index := transmute(Glyph) freetype.get_char_index( font.freetype_info, transmute(u32) codepoint )
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if prev_glyph_index != 0 && glyph_index != 0
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{
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kerning : freetype.Vector
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font.freetype_info.driver.clazz.get_kerning( font.freetype_info, transmute(u32) prev_codepoint, transmute(u32) codepoint, & kerning )
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}
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case .STB_TrueType:
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kern := stbtt.GetCodepointKernAdvance( & font.stbtt_info, prev_codepoint, codepoint )
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return kern
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}
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return -1
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}
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parser_get_font_vertical_metrics :: #force_inline proc "contextless" ( font : ^ParserFontInfo ) -> (ascent, descent, line_gap : i32 )
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{
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switch font.kind
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{
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case .Freetype:
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case .STB_TrueType:
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stbtt.GetFontVMetrics( & font.stbtt_info, & ascent, & descent, & line_gap )
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}
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return
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}
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parser_get_glyph_box :: #force_inline proc ( font : ^ParserFontInfo, glyph_index : Glyph ) -> (bounds_0, bounds_1 : Vec2i)
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{
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switch font.kind
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{
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case .Freetype:
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freetype.load_glyph( font.freetype_info, c.uint(glyph_index), { .No_Bitmap, .No_Hinting, .No_Scale } )
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metrics := font.freetype_info.glyph.metrics
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bounds_0 = {i32(metrics.hori_bearing_x), i32(metrics.hori_bearing_y - metrics.height)}
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bounds_1 = {i32(metrics.hori_bearing_x + metrics.width), i32(metrics.hori_bearing_y)}
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case .STB_TrueType:
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x0, y0, x1, y1 : i32
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success := cast(bool) stbtt.GetGlyphBox( & font.stbtt_info, i32(glyph_index), & x0, & y0, & x1, & y1 )
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assert( success )
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bounds_0 = { i32(x0), i32(y0) }
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bounds_1 = { i32(x1), i32(y1) }
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}
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return
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}
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parser_get_glyph_shape :: proc( font : ^ParserFontInfo, glyph_index : Glyph ) -> (shape : ParserGlyphShape, error : AllocatorError)
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{
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switch font.kind
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{
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case .Freetype:
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error := freetype.load_glyph( font.freetype_info, cast(u32) glyph_index, { .No_Bitmap, .No_Hinting, .No_Scale } )
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if error != .Ok {
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return
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}
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glyph := font.freetype_info.glyph
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if glyph.format != .Outline {
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return
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}
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/*
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convert freetype outline to stb_truetype shape
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freetype docs: https://freetype.org/freetype2/docs/glyphs/glyphs-6.html
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stb_truetype shape info:
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The shape is a series of contours. Each one starts with
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a STBTT_moveto, then consists of a series of mixed
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STBTT_lineto and STBTT_curveto segments. A lineto
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draws a line from previous endpoint to its x,y; a curveto
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draws a quadratic bezier from previous endpoint to
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its x,y, using cx,cy as the bezier control point.
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*/
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{
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FT_CURVE_TAG_CONIC :: 0x00
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FT_CURVE_TAG_ON :: 0x01
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FT_CURVE_TAG_CUBIC :: 0x02
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vertices, error := make( [dynamic]ParserGlyphVertex, 1024 )
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assert( error == .None )
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// TODO(Ed): This makes freetype second class I guess but VEFontCache doesn't have native support for freetype originally so....
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outline := & glyph.outline
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contours := transmute( [^]u16) outline.contours
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points := transmute( [^]freetype.Vector) outline.points
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tags := transmute( [^]u8) outline.tags
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// TODO(Ed): Review this, never tested before and its problably bad.
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for contour : i32 = 0; contour < i32(outline.n_contours); contour += 1
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{
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start := (contour == 0) ? 0 : i32(contours[ contour - 1 ] + 1)
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end := i32(contours[ contour ])
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for index := start; index < i32(outline.n_points); index += 1
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{
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point := points[ index ]
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tag := tags[ index ]
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if (tag & FT_CURVE_TAG_ON) != 0
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{
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if len(vertices) > 0 && !(vertices[len(vertices) - 1].type == .Move )
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{
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// Close the previous contour if needed
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append(& vertices, ParserGlyphVertex { type = .Line,
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x = i16(points[start].x), y = i16(points[start].y),
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contour_x0 = i16(0), contour_y0 = i16(0),
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contour_x1 = i16(0), contour_y1 = i16(0),
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padding = 0,
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})
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}
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append(& vertices, ParserGlyphVertex { type = .Move,
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x = i16(point.x), y = i16(point.y),
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contour_x0 = i16(0), contour_y0 = i16(0),
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contour_x1 = i16(0), contour_y1 = i16(0),
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padding = 0,
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})
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}
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else if (tag & FT_CURVE_TAG_CUBIC) != 0
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{
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point1 := points[ index + 1 ]
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point2 := points[ index + 2 ]
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append(& vertices, ParserGlyphVertex { type = .Cubic,
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x = i16(point2.x), y = i16(point2.y),
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contour_x0 = i16(point.x), contour_y0 = i16(point.y),
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contour_x1 = i16(point1.x), contour_y1 = i16(point1.y),
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padding = 0,
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})
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index += 2
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}
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else if (tag & FT_CURVE_TAG_CONIC) != 0
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{
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// TODO(Ed): This is using a very dead simple algo to convert the conic to a cubic curve
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// not sure if we need something more sophisticaated
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point1 := points[ index + 1 ]
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control_conv :: f32(0.5) // Conic to cubic control point distance
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to_float := f32(1.0 / 64.0)
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fp := Vec2 { f32(point.x), f32(point.y) } * to_float
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fp1 := Vec2 { f32(point1.x), f32(point1.y) } * to_float
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control1 := freetype.Vector {
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point.x + freetype.Pos( (fp1.x - fp.x) * control_conv * 64.0 ),
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point.y + freetype.Pos( (fp1.y - fp.y) * control_conv * 64.0 ),
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}
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control2 := freetype.Vector {
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point1.x + freetype.Pos( (fp.x - fp1.x) * control_conv * 64.0 ),
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point1.y + freetype.Pos( (fp.y - fp1.y) * control_conv * 64.0 ),
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}
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append(& vertices, ParserGlyphVertex { type = .Cubic,
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x = i16(point1.x), y = i16(point1.y),
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contour_x0 = i16(control1.x), contour_y0 = i16(control1.y),
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contour_x1 = i16(control2.x), contour_y1 = i16(control2.y),
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padding = 0,
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})
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index += 1
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}
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else
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{
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append(& vertices, ParserGlyphVertex { type = .Line,
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x = i16(point.x), y = i16(point.y),
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contour_x0 = i16(0), contour_y0 = i16(0),
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contour_x1 = i16(0), contour_y1 = i16(0),
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padding = 0,
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})
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}
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}
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// Close contour
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append(& vertices, ParserGlyphVertex { type = .Line,
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x = i16(points[start].x), y = i16(points[start].y),
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contour_x0 = i16(0), contour_y0 = i16(0),
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contour_x1 = i16(0), contour_y1 = i16(0),
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padding = 0,
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})
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}
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shape = vertices
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}
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case .STB_TrueType:
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stb_shape : [^]stbtt.vertex
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nverts := stbtt.GetGlyphShape( & font.stbtt_info, cast(i32) glyph_index, & stb_shape )
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shape_raw := transmute( ^runtime.Raw_Dynamic_Array) & shape
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shape_raw.data = stb_shape
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shape_raw.len = int(nverts)
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shape_raw.cap = int(nverts)
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shape_raw.allocator = runtime.nil_allocator()
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error = AllocatorError.None
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return
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}
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return
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}
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parser_is_glyph_empty :: #force_inline proc "contextless" ( font : ^ParserFontInfo, glyph_index : Glyph ) -> b32
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{
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switch font.kind
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{
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case .Freetype:
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error := freetype.load_glyph( font.freetype_info, cast(u32) glyph_index, { .No_Bitmap, .No_Hinting, .No_Scale } )
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if error == .Ok
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{
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if font.freetype_info.glyph.format == .Outline {
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return font.freetype_info.glyph.outline.n_points == 0
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}
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else if font.freetype_info.glyph.format == .Bitmap {
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return font.freetype_info.glyph.bitmap.width == 0 && font.freetype_info.glyph.bitmap.rows == 0;
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}
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}
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return false
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case .STB_TrueType:
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return stbtt.IsGlyphEmpty( & font.stbtt_info, cast(c.int) glyph_index )
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}
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return false
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}
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parser_scale :: #force_inline proc "contextless" ( font : ^ParserFontInfo, size : f32 ) -> f32
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{
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size_scale := size < 0.0 ? \
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parser_scale_for_pixel_height( font, -size ) \
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: parser_scale_for_mapping_em_to_pixels( font, size )
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// size_scale = 1.0
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return size_scale
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}
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parser_scale_for_pixel_height :: #force_inline proc "contextless" ( font : ^ParserFontInfo, size : f32 ) -> f32
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{
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switch font.kind {
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case .Freetype:
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freetype.set_pixel_sizes( font.freetype_info, 0, cast(u32) size )
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size_scale := size / cast(f32)font.freetype_info.units_per_em
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return size_scale
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case.STB_TrueType:
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return stbtt.ScaleForPixelHeight( & font.stbtt_info, size )
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}
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return 0
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}
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parser_scale_for_mapping_em_to_pixels :: #force_inline proc "contextless" ( font : ^ParserFontInfo, size : f32 ) -> f32
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{
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switch font.kind {
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case .Freetype:
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Inches_To_CM :: cast(f32) 2.54
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Points_Per_CM :: cast(f32) 28.3465
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CM_Per_Point :: cast(f32) 1.0 / DPT_DPCM
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CM_Per_Pixel :: cast(f32) 1.0 / DPT_PPCM
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DPT_DPCM :: cast(f32) 72.0 * Inches_To_CM // 182.88 points/dots per cm
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DPT_PPCM :: cast(f32) 96.0 * Inches_To_CM // 243.84 pixels per cm
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DPT_DPI :: cast(f32) 72.0
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// TODO(Ed): Don't assume the dots or pixels per inch.
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system_dpi :: DPT_DPI
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FT_Font_Size_Point_Unit :: 1.0 / 64.0
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FT_Point_10 :: 64.0
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points_per_em := (size / system_dpi ) * DPT_DPI
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freetype.set_char_size( font.freetype_info, 0, cast(freetype.F26Dot6) f32(points_per_em * FT_Point_10), cast(u32) DPT_DPI, cast(u32) DPT_DPI )
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size_scale := f32(f64(size) / cast(f64) font.freetype_info.units_per_em)
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return size_scale
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case .STB_TrueType:
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return stbtt.ScaleForMappingEmToPixels( & font.stbtt_info, size )
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}
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return 0
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}
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when false {
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parser_convert_conic_to_cubic_freetype :: proc( vertices : Array(ParserGlyphVertex), p0, p1, p2 : freetype.Vector, tolerance : f32 )
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{
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scratch : [Kilobyte * 4]u8
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scratch_arena : Arena; arena_init(& scratch_arena, scratch[:])
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points, error := make( Array(freetype.Vector), 256, allocator = arena_allocator( &scratch_arena) )
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assert(error == .None)
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append( & points, p0)
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append( & points, p1)
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append( & points, p2)
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|
|
|
to_float : f32 = 1.0 / 64.0
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|
control_conv :: f32(2.0 / 3.0) // Conic to cubic control point distance
|
|
|
|
for ; points.num > 1; {
|
|
p0 := points.data[0]
|
|
p1 := points.data[1]
|
|
p2 := points.data[2]
|
|
|
|
fp0 := Vec2{ f32(p0.x), f32(p0.y) } * to_float
|
|
fp1 := Vec2{ f32(p1.x), f32(p1.y) } * to_float
|
|
fp2 := Vec2{ f32(p2.x), f32(p2.y) } * to_float
|
|
|
|
delta_x := fp0.x - 2 * fp1.x + fp2.x;
|
|
delta_y := fp0.y - 2 * fp1.y + fp2.y;
|
|
distance := math.sqrt(delta_x * delta_x + delta_y * delta_y);
|
|
|
|
if distance <= tolerance
|
|
{
|
|
control1 := {
|
|
|
|
}
|
|
}
|
|
else
|
|
{
|
|
control2 := {
|
|
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|