Documentation
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Overview ¶
Package Units supports full range of CSS-style length units (em, px, dp, etc)
The unit is stored along with a value, and can be converted at a later point into a raw display pixel value using the Context which contains all the necessary reference values to perform the conversion. Typically the unit value is parsed early from a style and then converted later once the context is fully resolved. The Value also holds the converted value (Dots) so it can be used directly without further re-conversion.
'Dots' are used as term for underlying raw display pixels because "Pixel" and the px unit are actually not conventionally used as raw display pixels in the current HiDPI environment. See https://developer.mozilla.org/en/docs/Web/CSS/length -- 1 px = 1/96 in Also supporting dp = density-independent pixel = 1/160 in
Index ¶
- Constants
- Variables
- type Context
- func (uc *Context) Defaults()
- func (uc *Context) DotsToPx(val float32) float32
- func (uc *Context) PxToDots(val float32) float32
- func (uc *Context) Set(em, ex, ch, rem, vpw, vph, elw, elh float32)
- func (uc *Context) SetFont(em, ex, ch, rem float32)
- func (uc *Context) SetSizes(vpw, vph, elw, elh float32)
- func (uc *Context) ToDots(val float32, un Units) float32
- func (uc *Context) ToDotsFactor(un Units) float32
- type Units
- type Value
- func NewCh(val float32) Value
- func NewDot(val float32) Value
- func NewDp(val float32) Value
- func NewEm(val float32) Value
- func NewEx(val float32) Value
- func NewPct(val float32) Value
- func NewPt(val float32) Value
- func NewPx(val float32) Value
- func NewValue(val float32, un Units) Value
- func StringToValue(str string) Value
- func (v *Value) Convert(to Units, ctxt *Context) Value
- func (v *Value) Set(val float32, un Units)
- func (v *Value) SetCh(val float32)
- func (v *Value) SetDot(val float32)
- func (v *Value) SetDp(val float32)
- func (v *Value) SetEm(val float32)
- func (v *Value) SetEx(val float32)
- func (v *Value) SetFmInheritProp(key string, k ki.Ki, inherit, typ bool) (bool, error)
- func (v *Value) SetFmProp(key string, props ki.Props) (bool, error)
- func (v *Value) SetIFace(iface any, key string) error
- func (v *Value) SetPct(val float32)
- func (v *Value) SetPt(val float32)
- func (v *Value) SetPx(val float32)
- func (v *Value) SetString(str string)
- func (v *Value) String() string
- func (v *Value) ToDots(ctxt *Context) float32
- func (v *Value) ToDotsFixed(ctxt *Context) fixed.Int26_6
Constants ¶
const ( PxPerInch = 96.0 DpPerInch = 160.0 MmPerInch = 25.4 CmPerInch = 2.54 PtPerInch = 72.0 PcPerInch = 6.0 )
standard conversion factors -- Px = DPI-independent pixel instead of actual "dot" raw pixel
Variables ¶
var KiT_Units = kit.Enums.AddEnumAltLower(UnitsN, kit.NotBitFlag, nil, "")
var KiT_Value = kit.Types.AddType(&Value{}, ValueProps)
var UnitNames = [...]string{ Px: "px", Dp: "dp", Pct: "pct", Rem: "rem", Em: "em", Ex: "ex", Ch: "ch", Vw: "vw", Vh: "vh", Vmin: "vmin", Vmax: "vmax", Cm: "cm", Mm: "mm", Q: "q", In: "in", Pc: "pc", Pt: "pt", Dot: "dot", }
var ValueProps = ki.Props{ "style-prop": true, }
Functions ¶
This section is empty.
Types ¶
type Context ¶
type Context struct {
// DPI is dots-per-inch of the display
DPI float32
// FontEm is the point size of the font in raw dots (not points)
FontEm float32
// FontEx is the height x-height of font in points (size of 'x' glyph)
FontEx float32
// FontCh is the ch-size character size of font in points (width of '0' glyph)
FontCh float32
// FontRem is rem-size of font in points -- root Em size -- typically 12 point
FontRem float32
// VpW is viewport width in dots
VpW float32
// VpH is viewport height in dots
VpH float32
// ElW is width of surrounding contextual element in dots
ElW float32
// ElH is height of surrounding contextual element in dots
ElH float32
}
Context specifies everything about the current context necessary for converting the number into specific display-dependent pixels
func (*Context) SetFont ¶
SetFont sets the context values for fonts: note these are already in raw DPI dots, not points or anything else
func (*Context) SetSizes ¶
SetSizes sets the context values for non-font sizes -- el is ignored if zero
func (*Context) ToDotsFactor ¶
ToDotsFact returns factor needed to convert given unit into raw pixels (dots in DPI)
type Units ¶ added in v1.2.0
type Units int32
const ( // Px = pixels -- 1px = 1/96th of 1in -- these are NOT raw display pixels Px Units = iota // Dp = density-independent pixels -- 1dp = 1/160th of 1in Dp // Pct = percentage of surrounding contextual element Pct // Rem = font size of the root element -- defaults to 12pt scaled by DPI factor Rem // Em = font size of the element -- fallback to 12pt by default Em // Ex = x-height of the element's font (size of 'x' glyph) -- fallback to 0.5em by default Ex // Ch = width of the '0' glyph in the element's font -- fallback to 0.5em by default Ch // Vw = 1% of the viewport's width Vw // Vh = 1% of the viewport's height Vh // Vmin = 1% of the viewport's smaller dimension Vmin // Vmax = 1% of the viewport's larger dimension Vmax // Cm = centimeters -- 1cm = 96px/2.54 Cm // Mm = millimeters -- 1mm = 1/10th of cm Mm // Q = quarter-millimeters -- 1q = 1/40th of cm Q // In = inches -- 1in = 2.54cm = 96px In // Pc = picas -- 1pc = 1/6th of 1in Pc // Pt = points -- 1pt = 1/72th of 1in Pt // Dot = actual real display pixels -- generally only use internally Dot UnitsN )
func (*Units) FromString ¶ added in v1.2.0
func (Units) MarshalJSON ¶ added in v1.2.0
func (*Units) UnmarshalJSON ¶ added in v1.2.0
type Value ¶
Value and units, and converted value into raw pixels (dots in DPI)
func StringToValue ¶
StringToValue converts a string to a value representation.
func (*Value) SetFmInheritProp ¶
SetFmInheritProp sets value from property of given key name in inherited or type properties from given Ki.ki type -- returns true if property found and set, error for any errors in setting property
func (*Value) SetFmProp ¶
SetFmProp sets value from property of given key name in given list of properties -- returns true if property found and set, error for any errors in setting property
func (*Value) SetIFace ¶
SetIFace sets value from an interface value representation as from ki.Props key is optional property key for error message -- always logs the error
Source Files