{"id":93,"date":"2007-05-12T13:54:10","date_gmt":"2007-05-12T11:54:10","guid":{"rendered":" http:\/\/www.nsonic.de\/blog\/2007\/05\/richedit-on-a-transparent-background\/"},"modified":"2007-05-12T13:54:11","modified_gmt":"2007-05-12T11:54:11","slug":"richedit-on-a-transparent-background","status":"publish","type":"post","link":"https:\/\/www.nsonic.de\/blog\/2007\/05\/richedit-on-a-transparent-background\/","title":{"rendered":"Richedit on a transparent background"},"content":{"rendered":"

>
\n> I would like to have a Richedit box with a transparent background.
\n>
\n> To be more precise, I would like to be able to display the contents of a
\n> ..RTF file on the screen with a background graphic showing through.
\n>
\n> Does anyone know how to make this happen. Presumably, it is not just a
\n> matter of putting something in the background colour property (because
\n> I’ve looked and there is not “transparent”). However, I have seen other
\n> products which do have the ability to display an .RTF file on top of a
\n> graphic.
\n<\/em>
\nVon: Peter Below <\n100113.1101@compuserve.com \n \n>
\nBetreff: Re: Richedit on a transparent background
\nDatum: Dienstag, 5. Januar 1999 15:27 <\/p>\n

The rich edit control itself cannot be made transparent without a lot of
\nproblems. But you can get it to render its text onto any kind of canvas,
\ne.g. a bitmap.canvas or a TImage canvas.<\/p>\n

[code lang=”delphi”]procedure TForm1.Button2Click(Sender: TObject);
\nvar
\n imagecanvas: TCanvas;
\n fmt: TFormatRange;
\nbegin
\n imagecanvas := image1.canvas;
\n with fmt do begin
\n hdc:= imagecanvas.handle;
\n hdcTarget:= hdc;
\n \/\/ rect needs to be specified in twips (1\/1440 inch) as unit
\n rc:= Rect( 0, 0,
\n imagecanvas.cliprect.right * 1440 div pixelsperinch,
\n imagecanvas.cliprect.bottom * 1440 div pixelsperinch
\n );
\n rcPage:= rc;
\n chrg.cpMin := 0;
\n chrg.cpMax := richedit1.GetTextLen;
\n end;
\n SetBkMode( imagecanvas.Handle, TRANSPARENT );
\n richedit1.perform( EM_FORMATRANGE, 1, integer( @fmt ));
\n \/\/ next call frees some cached data
\n richedit1.perform( EM_FORMATRANGE, 0, 0 );
\n image1.refresh;
\n \/\/ refresh is necessary since the control only refreshes automatically
\n \/\/ if a canvas method is used to change its content.<\/p>\n

end;
\n[\/code]
\nThis assumes TImage contains a bitmap image. Add the richedit unit to your
\nUses clause (the one after the Implementation keyword).<\/p>\n

Peter Below (TeamB)
\n100113.1101@compuserve.com <\/p>\n

)
\nNo e-mail responses, please, unless explicitely requested!<\/p>\n

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

> > I would like to have a Richedit box with a transparent background. > > To be more precise, I would like…<\/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":[90,75,93],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p71Tml-1v","_links":{"self":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/93"}],"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=93"}],"version-history":[{"count":0,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/posts\/93\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/media?parent=93"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/categories?post=93"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nsonic.de\/blog\/wp-json\/wp\/v2\/tags?post=93"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}