[英]PNG image from imagelist
如何从TImageList
拍摄图片并将其放入TImage
(或将其作为TGraphic
返回)?
重要的一点是, TImageList
可以包含32bpp的alpha混合图像。 目的是获得这些alpha混合图像之一,并将其放置在TImage
。 这意味着在某个时候我可能需要TGraphic
。 尽管严格来说,我的问题是关于将图像从ImageList放入Image 。 如果没有中间的TGraphic
就可以实现,那也很好。
我们想要一个函数的胆量:
procedure GetImageListImageIntoImage(SourceImageList: TCustomImageList;
ImageIndex: Integer; TargetImage: TImage);
begin
//TODO: Figure this out.
//Neither SourceImageList.GetIcon nor SourceImageList.GetBitmap preserve the alpha channel
end;
还可以使用另一个有用的中间帮助器功能:
function ImageListGetGraphic(ImageList: TCustomImageList; ImageIndex: Integer): TGraphic;
var
// ico: TIcon;
bmp: TBitmap;
begin
{Doesn't work; loses alpha channel.
Windows Icon format can support 32bpp alpha bitmaps. But it just doesn't work here
ico := TIcon.Create;
ImageList.GetIcon(ImageIndex, ico, dsTransparent, itImage);
Result := ico;
}
{Doesn't work; loses alpha channel.
Windows does support 32bpp alpha bitmaps. But it just doesn't work here
bmp := TBitmap.Create;
bmp.PixelFormat := pf32bit;
Imagelist.GetBitmap(ImageIndex, bmp);
Result := bmp;
}
end;
让我们将原始过程转换为:
procedure GetImageListImageIntoImage(SourceImageList: TCustomImageList; ImageIndex: Integer; TargetImage: TImage);
var
g: TGraphic;
begin
g := ImageListGetGraphic(SourceImageList, ImageIndex);
TargetImage.Picture.Graphic := g; //Assignment of TGraphic does a copy
g.Free;
end;
我也有一些随机的东西:
Image1.Picture := TPicture(ImageList1.Components[0]);
但这不能编译。
PS我有德尔福2010
ImageList1.GetBitmap(0, Image1.Picture.Bitmap);
从ImageList获取透明图形的例程:
function ImageListGetGraphic(ImageList: TCustomImageList; ImageIndex: Integer): TGraphic;
var
ico: HICON;
// png: TPngImage;
// icon: TIcon;
// bmp: TBitmap;
wicbmp: IWICBitmap;
wi: TWicImage;
begin
{ //Works. Uses our own better Wic library.
ico := ImageList_GetIcon(ImageList.Handle, ImageIndex, ILD_NORMAL);
Result := TWicGraphic.FromHICON(ico);
DestroyIcon(ico);}
//Works, uses the built-in Delphi TWicImage (careful of VCL bugs)
ico := ImageList_GetIcon(ImageList.Handle, ImageIndex, ILD_NORMAL);
wi := TWICImage.Create; //Due to a bug in the VCL, you must construct the TWicImage before trying to access the Wic ImagingFactory
OleCheck(TWicImage.ImagingFactory.CreateBitmapFromHICON(ico, wicbmp));
wi.Handle := wicbmp;
Result := wi;
{ //Doesn't work, loses alpha channel
icon := TIcon.Create;
ImageList.GetIcon(ImageIndex, icon, dsTransparent, itImage);
Result := icon;
}
{ //Doesn't work, loses alpha channel
bmp := TBitmap.Create;
bmp.PixelFormat := pf32bit;
Imagelist.GetBitmap(ImageIndex, bmp);
Result := bmp;
}
{ //Fails: cannot assign a TIcon to a TPngImage
icon := TIcon.Create;
ImageList.GetIcon(ImageIndex, icon, ImgList.dsNormal, itImage);
png := TPngImage.Create;
png.Assign(icon);
Result := png;
icon.Free;
}
{ //Working failure; doesn't support stretched drawing (e.g. TImage.Stretch = true)
icon := TIcon.Create;
ImageList.GetIcon(ImageIndex, icon, ImgList.dsNormal, itImage);
Result := ico;
}
end;
用法示例:
g: TGraphic;
g := ImageListGetGraphic(ImageList1, 7);
Image1.Picture.Graphic := g;
g.Free;
注意 :任何发布到公共领域的代码。 无需注明出处。
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