canvas

package
v1.0.3 Latest Latest
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 Go to latest Published: Feb 26, 2021 License: MIT Imports: 27 Imported by: 5

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func AdjustImageForColor 

func AdjustImageForColor(mask image.Image, width int, height int, col color.Color) image.Image

func Asset 

func Asset(name string) ([]byte, error)

Asset loads and returns the asset for the given name. It returns an error if the asset could not be found or could not be loaded.

func AssetDir 

func AssetDir(name string) ([]string, error)

AssetDir returns the file names below a certain directory embedded in the file by go-bindata. For example if you run go-bindata on data/... and data contains the following hierarchy: 

data/
  foo.txt
  img/
    a.png
    b.png

then AssetDir("data") would return []string{"foo.txt", "img"} AssetDir("data/img") would return []string{"a.png", "b.png"} AssetDir("foo.txt") and AssetDir("notexist") would return an error AssetDir("") will return []string{"data"}.

func AssetInfo 

func AssetInfo(name string) (os.FileInfo, error)

AssetInfo loads and returns the asset info for the given name. It returns an error if the asset could not be found or could not be loaded.

func AssetNames 

func AssetNames() []string

AssetNames returns the names of the assets.

func CharPositions 

func CharPositions(family string, size float64, bold bool, italic bool, text string) ([]int, error)

func CohenSutherland 

func CohenSutherland(x1, y1, x2, y2, left, top, right, bottom int) (int, int, int, int, bool)

func Decode 

func Decode(r io.Reader) (image.Image, error)

func DecodeAll 

func DecodeAll(r io.Reader) ([]image.Image, error)

func DecodeConfig 

func DecodeConfig(r io.Reader) (image.Config, error)

func Font 

func Font(family string, size float64, bold bool, italic bool) (result *truetype.Font, face font.Face, err error)

func MakeFontFace 

func MakeFontFace(f *truetype.Font, size float64) font.Face

func MeasureText 

func MeasureText(family string, size float64, bold bool, italic bool, text string, multiline bool) (int, int, error)

func MeasureTextFreeType 

func MeasureTextFreeType(family string, size float64, bold bool, italic bool, text string, multiline bool) (int, int, error)

func MustAsset 

func MustAsset(name string) []byte

MustAsset is like Asset but panics when Asset would return an error. It simplifies safe initialization of global variables.

func ParseFont 

func ParseFont(b []byte) (*truetype.Font, error)

ParseFont just calls the Parse function from the freetype/truetype package. It is provided here so that code that imports this package doesn't need to also include the freetype/truetype package.

func Pt 

func Pt(x, y int) fixed.Point26_6

Pt converts from a co-ordinate pair measured in pixels to a fixed.Point26_6 co-ordinate pair measured in fixed.Int26_6 units.

func RestoreAsset 

func RestoreAsset(dir, name string) error

RestoreAsset restores an asset under the given directory

func RestoreAssets 

func RestoreAssets(dir, name string) error

RestoreAssets restores an asset under the given directory recursively

Types

type CanvasDirect 

type CanvasDirect struct {
	stats.Obj
	// contains filtered or unexported fields
}

func NewCanvas 

func NewCanvas(width int, height int) *CanvasDirect

func NewCanvasWindow 

func NewCanvasWindow(width int, height int) *CanvasDirect

func (*CanvasDirect) ClipIn 

func (c *CanvasDirect) ClipIn(x, y, width, height int)

func (*CanvasDirect) ClipInTranslated 

func (c *CanvasDirect) ClipInTranslated(x, y, width, height int)

func (*CanvasDirect) ClippedRegion 

func (c *CanvasDirect) ClippedRegion() (int, int, int, int)

func (*CanvasDirect) DrawImage 

func (c *CanvasDirect) DrawImage(x int, y int, img image.Image)

func (*CanvasDirect) DrawLine 

func (c *CanvasDirect) DrawLine(x1 int, y1 int, x2 int, y2 int, width int, color color.Color)

func (*CanvasDirect) DrawPoint 

func (c *CanvasDirect) DrawPoint(x int, y int, color color.Color)

func (*CanvasDirect) DrawRect 

func (c *CanvasDirect) DrawRect(x int, y int, width int, height int, color color.Color, strokeWidth int)

func (*CanvasDirect) DrawText 

func (c *CanvasDirect) DrawText(x int, y int, text string, fontFamily string, fontSize float64, colr color.Color, underline bool)

func (*CanvasDirect) DrawTextMultiline 

func (c *CanvasDirect) DrawTextMultiline(x int, y int, width int, height int, hAlign HAlign, vAlign VAlign, text string, colr color.Color, fontFamily string, fontSize float64, underline bool)

func (*CanvasDirect) FillEntire 

func (c *CanvasDirect) FillEntire(colr color.Color)

func (*CanvasDirect) FillRect 

func (c *CanvasDirect) FillRect(x int, y int, width int, height int, colr color.Color)

func (*CanvasDirect) Image 

func (c *CanvasDirect) Image() *image.RGBA

func (*CanvasDirect) Load 

func (c *CanvasDirect) Load()

func (*CanvasDirect) MakeScriptLine 

func (c *CanvasDirect) MakeScriptLine(x1, y1, x2, y2, width float64) *DrawScript

func (*CanvasDirect) MakeScriptLineBresenham 

func (c *CanvasDirect) MakeScriptLineBresenham(x1 float64, y1 float64, x2 float64, y2 float64) *DrawScript

func (*CanvasDirect) MakeScriptLineWu 

func (c *CanvasDirect) MakeScriptLineWu(x1, y1, x2, y2 float64) *DrawScript

func (*CanvasDirect) MixPixel 

func (c *CanvasDirect) MixPixel(x int, y int, rgba color.Color)

func (*CanvasDirect) Save 

func (c *CanvasDirect) Save()

func (*CanvasDirect) State 

func (c *CanvasDirect) State() CanvasDirectState

func (*CanvasDirect) Translate 

func (c *CanvasDirect) Translate(x, y int)

func (*CanvasDirect) TranslatedX 

func (c *CanvasDirect) TranslatedX() int

func (*CanvasDirect) TranslatedY 

func (c *CanvasDirect) TranslatedY() int

type CanvasDirectState 

type CanvasDirectState struct {
	TranslateX int
	TranslateY int

	ClipX      int
	ClipY      int
	ClipWidth  int
	ClipHeight int
}

func (*CanvasDirectState) String 

func (c *CanvasDirectState) String() string

type Context 

type Context struct {
	// contains filtered or unexported fields
}

A Context holds the state for drawing text in a given font and size.

func FontContext 

func FontContext(family string, size float64, bold bool, italic bool, color color.Color) (*Context, error)

func NewContext 

func NewContext() *Context

NewContext creates a new Context.

func (*Context) DrawString 

func (c *Context) DrawString(s string, p fixed.Point26_6) (fixed.Point26_6, error)

DrawString draws s at p and returns p advanced by the text extent. The text is placed so that the left edge of the em square of the first character of s and the baseline intersect at p. The majority of the affected pixels will be above and to the right of the point, but some may be below or to the left. For example, drawing a string that starts with a 'J' in an italic font may affect pixels below and left of the point.

p is a fixed.Point26_6 and can therefore represent sub-pixel positions.

func (*Context) PointToFixed 

func (c *Context) PointToFixed(x float64) fixed.Int26_6

PointToFixed converts the given number of points (as in "a 12 point font") into a 26.6 fixed point number of pixels.

func (*Context) SetClip 

func (c *Context) SetClip(clip image.Rectangle)

SetClip sets the clip rectangle for drawing.

func (*Context) SetDPI 

func (c *Context) SetDPI(dpi float64)

SetDPI sets the screen resolution in dots per inch.

func (*Context) SetDst 

func (c *Context) SetDst(dst draw.Image)

SetDst sets the destination image for draw operations.

func (*Context) SetFont 

func (c *Context) SetFont(f *truetype.Font)

SetFont sets the font used to draw text.

func (*Context) SetFontSize 

func (c *Context) SetFontSize(fontSize float64)

SetFontSize sets the font size in points (as in "a 12 point font").

func (*Context) SetHinting 

func (c *Context) SetHinting(hinting font.Hinting)

SetHinting sets the hinting policy.

func (*Context) SetSrc 

func (c *Context) SetSrc(src image.Image)

SetSrc sets the source image for draw operations. This is typically an image.Uniform.

type DrawScript 

type DrawScript struct {
	Bounds image.Rectangle
	// contains filtered or unexported fields
}

func NewDrawScript 

func NewDrawScript() *DrawScript

func (*DrawScript) DrawToRGBA 

func (c *DrawScript) DrawToRGBA(img *image.RGBA, col color.Color)

func (*DrawScript) MixPixel 

func (c *DrawScript) MixPixel(img *image.RGBA, x int, y int, rgba color.Color, intensity uint32)

type DrawScriptHorLine 

type DrawScriptHorLine struct {
	X1 int
	X2 int
	Y  int
	C  float64
}

type DrawScriptPoint 

type DrawScriptPoint struct {
	X int
	Y int
	C float64
}

type FontInfo 

type FontInfo struct {
	// contains filtered or unexported fields
}

type FontMeasureData 

type FontMeasureData struct {
	Width  int
	Height int
}

func GetFontMeasureData 

func GetFontMeasureData(family string, size float64, bold bool, italic bool, text string, multiline bool) *FontMeasureData

type HAlign 

type HAlign int
const HAlignCenter HAlign = 1
const HAlignLeft HAlign = 0
const HAlignRight HAlign = 2

type VAlign 

type VAlign int
const VAlignBottom VAlign = 2
const VAlignCenter VAlign = 1
const VAlignTop VAlign = 0

Source Files

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