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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build windows
package windriver
import (
"image"
"image/draw"
"sync"
"syscall"
"golang.org/x/exp/shiny/driver/internal/swizzle"
)
type bufferImpl struct {
hbitmap syscall.Handle
buf []byte
rgba image.RGBA
size image.Point
mu sync.Mutex
nUpload uint32
released bool
cleanedUp bool
}
func (b *bufferImpl) Size() image.Point { return b.size }
func (b *bufferImpl) Bounds() image.Rectangle { return image.Rectangle{Max: b.size} }
func (b *bufferImpl) RGBA() *image.RGBA { return &b.rgba }
func (b *bufferImpl) preUpload() {
// Check that the program hasn't tried to modify the rgba field via the
// pointer returned by the bufferImpl.RGBA method. This check doesn't catch
// 100% of all cases; it simply tries to detect some invalid uses of a
// screen.Buffer such as:
// *buffer.RGBA() = anotherImageRGBA
if len(b.buf) != 0 && len(b.rgba.Pix) != 0 && &b.buf[0] != &b.rgba.Pix[0] {
panic("windriver: invalid Buffer.RGBA modification")
}
b.mu.Lock()
defer b.mu.Unlock()
if b.released {
panic("windriver: Buffer.Upload called after Buffer.Release")
}
if b.nUpload == 0 {
swizzle.BGRA(b.buf)
}
b.nUpload++
}
func (b *bufferImpl) postUpload() {
b.mu.Lock()
defer b.mu.Unlock()
b.nUpload--
if b.nUpload != 0 {
return
}
if b.released {
go b.cleanUp()
} else {
swizzle.BGRA(b.buf)
}
}
func (b *bufferImpl) Release() {
b.mu.Lock()
defer b.mu.Unlock()
if !b.released && b.nUpload == 0 {
go b.cleanUp()
}
b.released = true
}
func (b *bufferImpl) cleanUp() {
b.mu.Lock()
if b.cleanedUp {
b.mu.Unlock()
panic("windriver: Buffer clean-up occurred twice")
}
b.cleanedUp = true
b.mu.Unlock()
b.rgba.Pix = nil
_DeleteObject(b.hbitmap)
}
func (b *bufferImpl) blitToDC(dc syscall.Handle, dp image.Point, sr image.Rectangle) error {
b.preUpload()
defer b.postUpload()
dr := sr.Add(dp.Sub(sr.Min))
return copyBitmapToDC(dc, dr, b.hbitmap, sr, draw.Src)
}
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