NewAlpha

本文整理汇总了Golang中image.NewAlpha函数的典型用法代码示例。如果您正苦于以下问题：Golang NewAlpha函数的具体用法？Golang NewAlpha怎么用？Golang NewAlpha使用的例子？那么恭喜您, 这里精选的函数代码示例或许可以为您提供帮助。

在下文中一共展示了NewAlpha函数的20个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的Golang代码示例。

示例1: initLayout

// initLayout constructs two masks for drawing the battery and the remaining
// energy as well as sets the pixel bounds for drawing energy capacity.  the
// masks allow for simplified space-fills and reduced chance of pixel gaps.
func (app *App) initLayout() {
    var zeropt image.Point

    rectOutTop := image.Rectangle{Min: app.Layout.battRect.Min, Max: app.Layout.battRect.Min.Add(image.Point{2, 2})}
    rectOutBottom := rectOutTop.Add(image.Point{Y: app.Layout.battRect.Size().Y - rectOutTop.Size().Y})
    capRect := image.Rectangle{
        Min: image.Point{X: rectOutTop.Min.X, Y: rectOutTop.Max.Y},
        Max: image.Point{X: rectOutBottom.Max.X, Y: rectOutBottom.Min.Y},
    }
    bodyRect := app.Layout.battRect
    bodyRect.Min.X = capRect.Max.X

    // energy will be drawn under the battery shell.  The only place where it
    // is not safe to draw energy is outside the battery on the positive end.
    energyMask := image.NewAlpha(app.Layout.battRect)
    draw.Draw(energyMask, app.Layout.battRect, opaque, zeropt, draw.Over)
    draw.Draw(energyMask, rectOutTop, transparent, zeropt, draw.Src)
    draw.Draw(energyMask, rectOutBottom, transparent, zeropt, draw.Src)
    app.maskEnergy = energyMask

    // the body uses the same mask as the energy with additional transparency
    // inside the battery's shell.  the mask construction is complex because
    // area inside the cap may be exposed.
    bodyMask := image.NewAlpha(app.Layout.battRect)
    draw.Draw(bodyMask, app.Layout.battRect, energyMask, app.Layout.battRect.Min, draw.Over)
    bodyMaskRect := shrinkRect(bodyRect, app.Layout.thickness)
    draw.Draw(bodyMask, bodyMaskRect, transparent, zeropt, draw.Src)
    capMaskRect := shrinkRect(capRect, app.Layout.thickness)
    capMaskRect.Max.X += 2 * app.Layout.thickness
    draw.Draw(bodyMask, capMaskRect, transparent, zeropt, draw.Src)
    app.maskBattery = bodyMask

    // create a freetype.Context to render text.  each time the context is used
    // it must have its SetDst method called.
    app.tt = freetype.NewContext()
    app.tt.SetSrc(black)
    app.tt.SetClip(app.Layout.textRect)
    app.tt.SetDPI(app.Layout.DPI)
    app.tt.SetFont(app.Layout.font)
    app.tt.SetFontSize(app.Layout.fontSize)
    ttopt := &truetype.Options{
        Size: app.Layout.fontSize,
        DPI:  app.Layout.DPI,
    }
    ttface := truetype.NewFace(app.Layout.font, ttopt)
    app.font = &font.Drawer{
        Src:  black,
        Face: ttface,
    }

    // the rectangle in which energy is drawn needs to account for thickness to
    // make the visible percentage more accurate.  after adjustment reduce the
    // energy rect to account for the account of energy drained.  the energy
    // mask makes computing Y bounds largely irrelevant.
    app.minEnergy = capMaskRect.Min.X
    app.maxEnergy = bodyMaskRect.Max.X
}

开发者ID:bmatsuo，项目名称:dockapp-go，代码行数:60，代码来源:main.go

示例2: NewDrawableSize

// NewDrawableSize returns a new draw.Image with the same type as p and the given bounds.
// If p is not a draw.Image, another type is used.
func NewDrawableSize(p image.Image, r image.Rectangle) draw.Image {
    switch p := p.(type) {
    case *image.RGBA:
        return image.NewRGBA(r)
    case *image.RGBA64:
        return image.NewRGBA64(r)
    case *image.NRGBA:
        return image.NewNRGBA(r)
    case *image.NRGBA64:
        return image.NewNRGBA64(r)
    case *image.Alpha:
        return image.NewAlpha(r)
    case *image.Alpha16:
        return image.NewAlpha16(r)
    case *image.Gray:
        return image.NewGray(r)
    case *image.Gray16:
        return image.NewGray16(r)
    case *image.Paletted:
        pl := make(color.Palette, len(p.Palette))
        copy(pl, p.Palette)
        return image.NewPaletted(r, pl)
    case *image.CMYK:
        return image.NewCMYK(r)
    default:
        return image.NewRGBA(r)
    }
}

开发者ID:cautio，项目名称:imageserver，代码行数:30，代码来源:util.go

示例3: rasterize

// rasterize returns the advance width, glyph mask and integer-pixel offset
// to render the given glyph at the given sub-pixel offsets.
// The 24.8 fixed point arguments fx and fy must be in the range [0, 1).
func (c *Context) rasterize(glyph truetype.Index, fx, fy raster.Fix32) (
    raster.Fix32, *image.Alpha, image.Point, error) {

    if err := c.glyphBuf.Load(c.font, c.scale, glyph, truetype.Hinting(c.hinting)); err != nil {
        return 0, nil, image.Point{}, err
    }
    // Calculate the integer-pixel bounds for the glyph.
    xmin := int(fx+raster.Fix32(c.glyphBuf.B.XMin<<2)) >> 8
    ymin := int(fy-raster.Fix32(c.glyphBuf.B.YMax<<2)) >> 8
    xmax := int(fx+raster.Fix32(c.glyphBuf.B.XMax<<2)+0xff) >> 8
    ymax := int(fy-raster.Fix32(c.glyphBuf.B.YMin<<2)+0xff) >> 8
    if xmin > xmax || ymin > ymax {
        return 0, nil, image.Point{}, errors.New("freetype: negative sized glyph")
    }
    // A TrueType's glyph's nodes can have negative co-ordinates, but the
    // rasterizer clips anything left of x=0 or above y=0. xmin and ymin
    // are the pixel offsets, based on the font's FUnit metrics, that let
    // a negative co-ordinate in TrueType space be non-negative in
    // rasterizer space. xmin and ymin are typically <= 0.
    fx += raster.Fix32(-xmin << 8)
    fy += raster.Fix32(-ymin << 8)
    // Rasterize the glyph's vectors.
    c.r.Clear()
    e0 := 0
    for _, e1 := range c.glyphBuf.End {
        c.drawContour(c.glyphBuf.Point[e0:e1], fx, fy)
        e0 = e1
    }
    a := image.NewAlpha(image.Rect(0, 0, xmax-xmin, ymax-ymin))
    c.r.Rasterize(raster.NewAlphaSrcPainter(a))
    return raster.Fix32(c.glyphBuf.AdvanceWidth << 2), a, image.Point{xmin, ymin}, nil
}

开发者ID:smalllixin，项目名称:freetype-go，代码行数:35，代码来源:freetype.go

示例4: textBox

// textBox renders t into a tight fitting image
func (ig *ImageGraphics) textBox(t string, size int) image.Image {
    // Initialize the context.
    fg := image.NewUniform(color.Alpha{0xff})
    bg := image.NewUniform(color.Alpha{0x00})
    canvas := image.NewAlpha(image.Rect(0, 0, 400, 2*size))
    draw.Draw(canvas, canvas.Bounds(), bg, image.ZP, draw.Src)

    c := freetype.NewContext()
    c.SetDPI(dpi)
    c.SetFont(ig.font)
    c.SetFontSize(float64(size))
    c.SetClip(canvas.Bounds())
    c.SetDst(canvas)
    c.SetSrc(fg)

    // Draw the text.
    h := c.FUnitToPixelRU(ig.font.UnitsPerEm())
    pt := freetype.Pt(0, h)
    extent, err := c.DrawString(t, pt)
    if err != nil {
        log.Println(err)
        return nil
    }
    // log.Printf("text %q, extent: %v", t, extent)
    return canvas.SubImage(image.Rect(0, 0, int(extent.X/256), h*5/4))
}

开发者ID:ajstarks，项目名称:chart，代码行数:27，代码来源:image.go

示例5: main

func main() {
    var err error
    gophersImage, _, err = common.AssetImage("gophers.jpg", ebiten.FilterNearest)
    if err != nil {
        log.Fatal(err)
    }
    fiveyearsImage, _, err = common.AssetImage("fiveyears.jpg", ebiten.FilterNearest)
    if err != nil {
        log.Fatal(err)
    }
    maskImage, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
    if err != nil {
        log.Fatal(err)
    }

    as := image.Point{128, 128}
    a := image.NewAlpha(image.Rectangle{image.ZP, as})
    for j := 0; j < as.Y; j++ {
        for i := 0; i < as.X; i++ {
            r := as.X / 2
            d := math.Sqrt(float64((i-r)*(i-r) + (j-r)*(j-r)))
            b := uint8(max(0, min(0xff, 3*0xff-int(d*3*0xff)/r)))
            a.SetAlpha(i, j, color.Alpha{b})
        }
    }
    spotLightImage, err = ebiten.NewImageFromImage(a, ebiten.FilterNearest)
    if err != nil {
        log.Fatal(err)
    }
    if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Masking (Ebiten Demo)"); err != nil {
        log.Fatal(err)
    }
}

开发者ID:carriercomm，项目名称:ebiten，代码行数:33，代码来源:main.go