{"id":147,"date":"2007-05-12T16:11:54","date_gmt":"2007-05-12T14:11:54","guid":{"rendered":" http:\/\/www.nsonic.de\/blog\/2007\/05\/drawtransparent-bitmaps\/"},"modified":"2007-05-12T16:11:56","modified_gmt":"2007-05-12T14:11:56","slug":"drawtransparent-bitmaps","status":"publish","type":"post","link":"https:\/\/www.nsonic.de\/blog\/2007\/05\/drawtransparent-bitmaps\/","title":{"rendered":"DrawTransparent Bitmaps"},"content":{"rendered":"

>Sam King wrote:
\n>
\n>> I want overlay bitmap2 over bitmap1
\n>> The bitmap2 should be on top of bitmap1
\n>> i.e. the end result should be that bitmap2 should also show bits of
\n>> bitmap1.
\n>> eg a grid pattern over a map. What is the best way in delphi to handle
\n>> this.
\n<\/em>
\nThere are two methods. One works using a timageList the other without. So
\nthe latter will work with other file types besides bmps. Here’s the code
\nfor both, it’s pretty clear how both work. The key thing is you must
\nspecify a transparent color:
\n
\n[code lang=”delphi”]procedure DrawTrans(DestCanvas: TCanvas; X,Y: smallint; SrcBitmap:
\nTBitmap; AColor: TColor);
\nvar ANDBitmap, ORBitmap: TBitmap;
\nCM: TCopyMode;
\nSrc: TRect;
\nbegin
\nANDBitmap:= NIL;
\nORBitmap:= NIL;
\ntry
\nANDBitmap:= TBitmap.Create;
\nORBitmap:= TBitmap.Create;
\nSrc := Bounds(0,0, SrcBitmap.Width, SrcBitmap.Height);
\nwith ORBitmap do begin
\nWidth:= SrcBitmap.Width;
\nHeight:= SrcBitmap.Height;
\nCanvas.Brush.Color := clBlack;
\nCanvas.CopyMode := cmSrcCopy;
\nCanvas.BrushCopy(Src, SrcBitmap, Src, AColor);
\nend;
\nwith ANDBitmap do begin
\nWidth:= SrcBitmap.Width;
\nHeight:= SrcBitmap.Height;
\nCanvas.Brush.Color := clWhite;
\nCanvas.CopyMode := cmSrcInvert;
\nCanvas.BrushCopy(Src, SrcBitmap, Src, AColor);
\nend;
\nwith DestCanvas do begin
\nCM := CopyMode;
\nCopyMode := cmSrcAnd;
\nDraw(X,Y, ANDBitmap);
\nCopyMode := cmSrcPaint;
\nDraw(X,Y, ORBitmap);
\nCopyMode := CM;
\nend;
\nfinally
\nANDBitmap.Free;
\nORBitmap.Free;
\nend;
\nend;
\n[\/code]<\/p>\n

The other way:
\n<\/b>
\n[code lang=”delphi”]abitmap:= tbitmap.Create;
\nimagelist1.Clear;
\nabitmap.LoadFromFile(‘1.bmp’);
\nimagelist1.AddMasked(abitmap, clNone);
\nabitmap.Empty;
\nabitmap.LoadFromFile(‘e1.bmp’);
\nimagelist1.AddMasked(abitmap, clWhite);
\nabitmap.Empty;
\nabitmap.LoadFromFile(‘h1.bmp’);
\nimagelist1.AddMasked(abitmap, clWhite);
\nimagelist1.Draw(image1.Canvas, 0, 0, 0);
\nimagelist1.Draw(image1.Canvas, 0, 0, 1);
\nimagelist1.Draw(image1.Canvas, 0, 0, 2);
\nabitmap.free;
\n[\/code]<\/p>\n

[tags]Delphi, Graphic[\/tags]<\/p>\n","protected":false},"excerpt":{"rendered":"

>Sam King wrote: > >> I want overlay bitmap2 over bitmap1 >> The bitmap2 should be on top of bitmap1 >> i.e. the…<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[11],"tags":[75,101],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p71Tml-2n","_links":{"self":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/147"}],"collection":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/comments?post=147"}],"version-history":[{"count":0,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/147\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/media?parent=147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/categories?post=147"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/tags?post=147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}