Documentation
¶
Overview ¶
The esizer subpackage defines the Sizer interface used within etxt and provides multiple ready-to-use implementations.
The only job of a Sizer is to determine how much space should be taken by each glyph. While font files already contain this information, using an interface as a middle layer allows etxt users to modify spacing manually and achieve specific effects like ignoring kerning, adding extra padding between letters or accounting for the extra space taken by custom glyph rasterizers.
Index ¶
- func DefaultAdvanceFunc(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6, buffer *sfnt.Buffer) fixed.Int26_6
- func DefaultKernFunc(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, ...) fixed.Int26_6
- func DefaultMetricsFunc(f *Font, size fixed.Int26_6, buffer *sfnt.Buffer) font.Metrics
- type AdvancePadSizer
- func (self *AdvancePadSizer) Advance(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
- func (self *AdvancePadSizer) Kern(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, ...) fixed.Int26_6
- func (self *AdvancePadSizer) Metrics(f *Font, size fixed.Int26_6) font.Metrics
- func (self *AdvancePadSizer) SetPadding(value int)
- func (self *AdvancePadSizer) SetPaddingFloat(value float64)
- func (self *AdvancePadSizer) SetPaddingFract(value fixed.Int26_6)
- type DefaultSizer
- type FixedSizer
- func (self *FixedSizer) Advance(*Font, GlyphIndex, fixed.Int26_6) fixed.Int26_6
- func (self *FixedSizer) Kern(*Font, GlyphIndex, GlyphIndex, fixed.Int26_6) fixed.Int26_6
- func (self *FixedSizer) Metrics(font *Font, size fixed.Int26_6) font.Metrics
- func (self *FixedSizer) SetAdvance(advance int)
- func (self *FixedSizer) SetAdvanceFloat(advance float64)
- func (self *FixedSizer) SetAdvanceFract(advance fixed.Int26_6)
- type Font
- type GlyphIndex
- type HorzPaddingSizer
- func (self *HorzPaddingSizer) Advance(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
- func (self *HorzPaddingSizer) Kern(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, ...) fixed.Int26_6
- func (self *HorzPaddingSizer) Metrics(f *Font, size fixed.Int26_6) font.Metrics
- func (self *HorzPaddingSizer) SetHorzPadding(value int)
- func (self *HorzPaddingSizer) SetHorzPaddingFloat(value float64)
- func (self *HorzPaddingSizer) SetHorzPaddingFract(value fixed.Int26_6)
- type NoKernSizer
- type Sizer
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DefaultAdvanceFunc ¶
func DefaultAdvanceFunc(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6, buffer *sfnt.Buffer) fixed.Int26_6
A default method to respond to glyph advance requests. Can be used while implementing your own sizers.
func DefaultKernFunc ¶
func DefaultKernFunc(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, size fixed.Int26_6, buffer *sfnt.Buffer) fixed.Int26_6
A default method to respond to glyph kern requests. Can be used while implementing your own sizers.
Types ¶
type AdvancePadSizer ¶
type AdvancePadSizer struct {
// contains filtered or unexported fields
}
Like HorzPaddingSizer, but adds the extra padding in the advance instead of the kern.
If you aren't modifying the glyphs, only padding them horizontally, use HorzPaddingSizer instead. This sizer is intended to deal with modified glyphs that have actually become wider.
func (*AdvancePadSizer) Advance ¶
func (self *AdvancePadSizer) Advance(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*AdvancePadSizer) Kern ¶
func (self *AdvancePadSizer) Kern(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*AdvancePadSizer) SetPadding ¶
func (self *AdvancePadSizer) SetPadding(value int)
Sets the configurable horizontal padding value, in pixels.
func (*AdvancePadSizer) SetPaddingFloat ¶
func (self *AdvancePadSizer) SetPaddingFloat(value float64)
Like AdvancePadSizer.SetPadding, but expecting a float64 instead of an int.
func (*AdvancePadSizer) SetPaddingFract ¶
func (self *AdvancePadSizer) SetPaddingFract(value fixed.Int26_6)
Like AdvancePadSizer.SetPadding, but expecting a fixed.Int26_6 instead of an int.
type DefaultSizer ¶
type DefaultSizer struct {
// contains filtered or unexported fields
}
The default Sizer used by etxt renderers. For more information about sizers, see the documentation of the Sizer interface.
func (*DefaultSizer) Advance ¶
func (self *DefaultSizer) Advance(font *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*DefaultSizer) Kern ¶
func (self *DefaultSizer) Kern(font *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
type FixedSizer ¶
type FixedSizer struct {
// contains filtered or unexported fields
}
A Sizer with a fixed advance between glyphs.
func (*FixedSizer) Advance ¶
func (self *FixedSizer) Advance(*Font, GlyphIndex, fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*FixedSizer) Kern ¶
func (self *FixedSizer) Kern(*Font, GlyphIndex, GlyphIndex, fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*FixedSizer) SetAdvance ¶
func (self *FixedSizer) SetAdvance(advance int)
Sets the fixed advance between characters.
func (*FixedSizer) SetAdvanceFloat ¶
func (self *FixedSizer) SetAdvanceFloat(advance float64)
Like FixedSizer.SetAdvance, but expecting a float64 instead of an int.
func (*FixedSizer) SetAdvanceFract ¶
func (self *FixedSizer) SetAdvanceFract(advance fixed.Int26_6)
Like FixedSizer.SetAdvance, but expcting a fixed.Int26_6 instead of an int.
type HorzPaddingSizer ¶
type HorzPaddingSizer struct {
// contains filtered or unexported fields
}
A Sizer that behaves like the default one, but with a configurable horizontal padding factor that's added to the kern between glyphs.
func (*HorzPaddingSizer) Advance ¶
func (self *HorzPaddingSizer) Advance(f *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*HorzPaddingSizer) Kern ¶
func (self *HorzPaddingSizer) Kern(f *Font, prevGlyphIndex GlyphIndex, currGlyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*HorzPaddingSizer) SetHorzPadding ¶
func (self *HorzPaddingSizer) SetHorzPadding(value int)
Sets the configurable horizontal padding value, in pixels.
func (*HorzPaddingSizer) SetHorzPaddingFloat ¶
func (self *HorzPaddingSizer) SetHorzPaddingFloat(value float64)
Like HorzPaddingSizer.SetHorzPadding, but expecting a float64 instead of an int.
func (*HorzPaddingSizer) SetHorzPaddingFract ¶
func (self *HorzPaddingSizer) SetHorzPaddingFract(value fixed.Int26_6)
Like HorzPaddingSizer.SetHorzPadding, but expecting a fixed.Int26_6 instead of an int.
type NoKernSizer ¶
type NoKernSizer struct {
// contains filtered or unexported fields
}
A default Sizer without kerning (the kern function always returns 0).
func (*NoKernSizer) Advance ¶
func (self *NoKernSizer) Advance(font *Font, glyphIndex GlyphIndex, size fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
func (*NoKernSizer) Kern ¶
func (self *NoKernSizer) Kern(*Font, GlyphIndex, GlyphIndex, fixed.Int26_6) fixed.Int26_6
Satisfies the Sizer interface.
type Sizer ¶
type Sizer interface {
Metrics(*Font, fixed.Int26_6) font.Metrics
Advance(*Font, GlyphIndex, fixed.Int26_6) fixed.Int26_6
Kern(*Font, GlyphIndex, GlyphIndex, fixed.Int26_6) fixed.Int26_6
}
When drawing or traversing glyphs, we need some information related to the "font metrics". For example, how much we need to advance after drawing a glyph or what's the kerning between a specific pair of glyphs.
Sizers are the interface that Renderers use to access that information.
You rarely need to care about Sizers, but they can be useful in the following cases:
- Disable kerning and adjust horizontal spacing.
- Make full size adjustments for a custom rasterizer (e.g., a rasterizer that puts glyphs into boxes, bubbles or frames).
Source Files