ebiten/image.go

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// Copyright 2014 Hajime Hoshi
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
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package ebiten
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import (
"fmt"
"image"
"image/color"
"runtime"
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"github.com/hajimehoshi/ebiten/internal/math"
"github.com/hajimehoshi/ebiten/internal/opengl"
"github.com/hajimehoshi/ebiten/internal/restorable"
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)
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// Image represents a rectangle set of pixels.
// The pixel format is alpha-premultiplied RGBA.
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// Image implements image.Image.
//
// Functions of Image never returns error as of 1.5.0-alpha, and error values are always nil.
type Image struct {
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restorable *restorable.Image
}
// Size returns the size of the image.
func (i *Image) Size() (width, height int) {
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return i.restorable.Size()
}
// Clear resets the pixels of the image into 0.
//
// When the image is disposed, Clear does nothing.
//
// Clear always returns nil as of 1.5.0-alpha.
func (i *Image) Clear() error {
i.restorable.Fill(0, 0, 0, 0)
return nil
}
// Fill fills the image with a solid color.
//
// When the image is disposed, Fill does nothing.
//
// Fill always returns nil as of 1.5.0-alpha.
func (i *Image) Fill(clr color.Color) error {
r, g, b, a := clr.RGBA()
i.restorable.Fill(uint8(r>>8), uint8(g>>8), uint8(b>>8), uint8(a>>8))
return nil
}
// DrawImage draws the given image on the receiver image.
//
// This method accepts the options.
// The parts of the given image at the parts of the destination.
// After determining parts to draw, this applies the geometry matrix and the color matrix.
//
// Here are the default values:
// SourceRect: nil. When SourceRect is nil, the whole source image is used.
// GeoM: Identity matrix
// ColorM: Identity matrix (that changes no colors)
// CompositeMode: CompositeModeSourceOver (regular alpha blending)
//
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// For drawing, the pixels of the argument image at the time of this call is adopted.
// Even if the argument image is mutated after this call,
// the drawing result is never affected.
//
// When the image is disposed, DrawImage does nothing.
//
// When the given image is as same as i, DrawImage panics.
//
// DrawImage works more efficiently as batches
// when the successive calls of DrawImages satisfies the below conditions:
//
// * All render targets are same (A in A.DrawImage(B, op))
// * All render sources are same (B in A.DrawImage(B, op))
// * All ColorM values are same
// * All CompositeMode values are same
//
// For more performance tips, see https://github.com/hajimehoshi/ebiten/wiki/Performance-Tips.
//
// DrawImage always returns nil as of 1.5.0-alpha.
func (i *Image) DrawImage(img *Image, options *DrawImageOptions) error {
if i == img {
panic("ebiten: Image.DrawImage: img must be different from the receiver")
}
if i.restorable == nil {
return nil
}
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// Calculate vertices before locking because the user can do anything in
// options.ImageParts interface without deadlock (e.g. Call Image functions).
if options == nil {
options = &DrawImageOptions{}
}
parts := options.ImageParts
// Parts is deprecated. This implementations is for backward compatibility.
if parts == nil && options.Parts != nil {
parts = imageParts(options.Parts)
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}
// ImageParts is deprecated. This implementations is for backward compatibility.
if parts != nil {
l := parts.Len()
for idx := 0; idx < l; idx++ {
sx0, sy0, sx1, sy1 := parts.Src(idx)
dx0, dy0, dx1, dy1 := parts.Dst(idx)
op := &DrawImageOptions{
ColorM: options.ColorM,
CompositeMode: options.CompositeMode,
}
r := image.Rect(sx0, sy0, sx1, sy1)
op.SourceRect = &r
op.GeoM.Scale(
float64(dx1-dx0)/float64(sx1-sx0),
float64(dy1-dy0)/float64(sy1-sy0))
op.GeoM.Translate(float64(dx0), float64(dy0))
op.GeoM.Concat(options.GeoM)
i.DrawImage(img, op)
}
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return nil
}
w, h := img.restorable.Size()
sx0, sy0, sx1, sy1 := 0, 0, w, h
if r := options.SourceRect; r != nil {
sx0 = r.Min.X
sy0 = r.Min.Y
sx1 = r.Max.X
sy1 = r.Max.Y
}
vs := vertices(sx0, sy0, sx1, sy1, w, h, &options.GeoM.impl)
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mode := opengl.CompositeMode(options.CompositeMode)
i.restorable.DrawImage(img.restorable, vs, &options.ColorM.impl, mode)
return nil
}
// Bounds returns the bounds of the image.
func (i *Image) Bounds() image.Rectangle {
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w, h := i.restorable.Size()
return image.Rect(0, 0, w, h)
}
// ColorModel returns the color model of the image.
func (i *Image) ColorModel() color.Model {
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return color.RGBAModel
}
// At returns the color of the image at (x, y).
//
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// This method loads pixels from GPU to system memory if necessary.
//
// This method can't be called before the main loop (ebiten.Run) starts (as of version 1.4.0-alpha).
func (i *Image) At(x, y int) color.Color {
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if i.restorable == nil {
return color.Transparent
}
// TODO: Error should be delayed until flushing. Do not panic here.
clr, err := i.restorable.At(x, y)
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if err != nil {
panic(err)
}
return clr
}
// Dispose disposes the image data. After disposing, the image becomes invalid.
// This is useful to save memory.
//
// The behavior of any functions for a disposed image is undefined.
//
// When the image is disposed, Dipose does nothing.
//
// Dipose always return nil as of 1.5.0-alpha.
func (i *Image) Dispose() error {
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if i.restorable == nil {
return nil
}
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i.restorable.Dispose()
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i.restorable = nil
runtime.SetFinalizer(i, nil)
return nil
}
// ReplacePixels replaces the pixels of the image with p.
//
// The given p must represent RGBA pre-multiplied alpha values. len(p) must equal to 4 * (image width) * (image height).
//
// ReplacePixels may be slow (as for implementation, this calls glTexSubImage2D).
//
// When len(p) is not 4 * (width) * (height), ReplacePixels panics.
//
// When the image is disposed, ReplacePixels does nothing.
//
// ReplacePixels always returns nil as of 1.5.0-alpha.
func (i *Image) ReplacePixels(p []uint8) error {
if i.restorable == nil {
return nil
}
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w, h := i.restorable.Size()
if l := 4 * w * h; len(p) != l {
panic(fmt.Sprintf("ebiten: len(p) was %d but must be %d", len(p), l))
}
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w2, h2 := math.NextPowerOf2Int(w), math.NextPowerOf2Int(h)
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pix := make([]uint8, 4*w2*h2)
for j := 0; j < h; j++ {
copy(pix[j*w2*4:], p[j*w*4:(j+1)*w*4])
}
i.restorable.ReplacePixels(pix)
return nil
}
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// A DrawImageOptions represents options to render an image on an image.
type DrawImageOptions struct {
SourceRect *image.Rectangle
GeoM GeoM
ColorM ColorM
CompositeMode CompositeMode
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// Deprecated (as of 1.5.0-alpha): Use SourceRect instead.
ImageParts ImageParts
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// Deprecated (as of 1.1.0-alpha): Use SourceRect instead.
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Parts []ImagePart
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}
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// NewImage returns an empty image.
//
// If width or height is less than 1 or more than MaxImageSize, NewImage panics.
//
// Error returned by NewImage is always nil as of 1.5.0-alpha.
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func NewImage(width, height int, filter Filter) (*Image, error) {
checkSize(width, height)
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r := restorable.NewImage(width, height, glFilter(filter), false)
r.Fill(0, 0, 0, 0)
i := &Image{r}
runtime.SetFinalizer(i, (*Image).Dispose)
return i, nil
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}
// newVolatileImage returns an empty 'volatile' image.
// A volatile image is always cleared at the start of a frame.
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//
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// This is suitable for offscreen images that pixels are changed often.
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//
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// Pixels in regular non-volatile images are saved at each end of a frame if the image
// is changed, and restored automatically from the saved pixels on GL context lost.
// On the other hand, pixels in volatile images are not saved.
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// Saving pixels is an expensive operation, and it is desirable to avoid it if possible.
//
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// Note that volatile images are internal only and will never be source of drawing.
//
// If width or height is less than 1 or more than MaxImageSize, newVolatileImage panics.
//
// Error returned by newVolatileImage is always nil as of 1.5.0-alpha.
func newVolatileImage(width, height int, filter Filter) *Image {
checkSize(width, height)
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r := restorable.NewImage(width, height, glFilter(filter), true)
r.Fill(0, 0, 0, 0)
i := &Image{r}
runtime.SetFinalizer(i, (*Image).Dispose)
return i
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}
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// NewImageFromImage creates a new image with the given image (source).
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//
// If source's width or height is less than 1 or more than MaxImageSize, NewImageFromImage panics.
//
// Error returned by NewImageFromImage is always nil as of 1.5.0-alpha.
func NewImageFromImage(source image.Image, filter Filter) (*Image, error) {
size := source.Bounds().Size()
checkSize(size.X, size.Y)
r := restorable.NewImageFromImage(source, glFilter(filter))
i := &Image{r}
runtime.SetFinalizer(i, (*Image).Dispose)
return i, nil
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}
func newImageWithScreenFramebuffer(width, height int, offsetX, offsetY float64) *Image {
checkSize(width, height)
r := restorable.NewScreenFramebufferImage(width, height, offsetX, offsetY)
i := &Image{r}
runtime.SetFinalizer(i, (*Image).Dispose)
return i
}
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// MaxImageSize represents the maximum width/height of an image.
const MaxImageSize = restorable.MaxImageSize
func checkSize(width, height int) {
if width <= 0 {
panic("ebiten: width must be more than 0")
}
if height <= 0 {
panic("ebiten: height must be more than 0")
}
if width > MaxImageSize {
panic(fmt.Sprintf("ebiten: width (%d) must be less than or equal to %d", width, MaxImageSize))
}
if height > MaxImageSize {
panic(fmt.Sprintf("ebiten: height (%d) must be less than or equal to %d", height, MaxImageSize))
}
}