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// Copyright 2010 The Walk 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 walk
import (
"syscall"
"unsafe"
)
import (
"github.com/lxn/win"
)
type Metafile struct {
hdc win.HDC
hemf win.HENHMETAFILE
size Size
}
func NewMetafile(referenceCanvas *Canvas) (*Metafile, error) {
hdc := win.CreateEnhMetaFile(referenceCanvas.hdc, nil, nil, nil)
if hdc == 0 {
return nil, newError("CreateEnhMetaFile failed")
}
return &Metafile{hdc: hdc}, nil
}
func NewMetafileFromFile(filePath string) (*Metafile, error) {
hemf := win.GetEnhMetaFile(syscall.StringToUTF16Ptr(filePath))
if hemf == 0 {
return nil, newError("GetEnhMetaFile failed")
}
mf := &Metafile{hemf: hemf}
err := mf.readSizeFromHeader()
if err != nil {
return nil, err
}
return mf, nil
}
func (mf *Metafile) Dispose() {
mf.ensureFinished()
if mf.hemf != 0 {
win.DeleteEnhMetaFile(mf.hemf)
mf.hemf = 0
}
}
func (mf *Metafile) Save(filePath string) error {
hemf := win.CopyEnhMetaFile(mf.hemf, syscall.StringToUTF16Ptr(filePath))
if hemf == 0 {
return newError("CopyEnhMetaFile failed")
}
win.DeleteEnhMetaFile(hemf)
return nil
}
func (mf *Metafile) readSizeFromHeader() error {
var hdr win.ENHMETAHEADER
if win.GetEnhMetaFileHeader(mf.hemf, uint32(unsafe.Sizeof(hdr)), &hdr) == 0 {
return newError("GetEnhMetaFileHeader failed")
}
mf.size = Size{
int(hdr.RclBounds.Right - hdr.RclBounds.Left),
int(hdr.RclBounds.Bottom - hdr.RclBounds.Top),
}
return nil
}
func (mf *Metafile) ensureFinished() error {
if mf.hdc == 0 {
if mf.hemf == 0 {
return newError("already disposed")
} else {
return nil
}
}
mf.hemf = win.CloseEnhMetaFile(mf.hdc)
if mf.hemf == 0 {
return newError("CloseEnhMetaFile failed")
}
mf.hdc = 0
return mf.readSizeFromHeader()
}
func (mf *Metafile) Size() Size {
return mf.size
}
func (mf *Metafile) draw(hdc win.HDC, location Point) error {
return mf.drawStretched(hdc, Rectangle{location.X, location.Y, mf.size.Width, mf.size.Height})
}
func (mf *Metafile) drawStretched(hdc win.HDC, bounds Rectangle) error {
rc := bounds.toRECT()
if !win.PlayEnhMetaFile(hdc, mf.hemf, &rc) {
return newError("PlayEnhMetaFile failed")
}
return nil
}
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