PGdkPixbuf from stream
lazarus / 39-Graphics

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mrdebug · 2010-05-20 15:20

Does anybody knows how to create a new PGdkPixbuf from byte array or
stream? There isn't gdk_pixbuf_new_from_stream gtk2 function in pfc.

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theo · 2010-05-20 16:25

What do you want to achieve?

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mrdebug · 2010-05-20 16:39

I'm writing a client for a videoserver. The Lcl components are too
slow to show a jpeg sequence. To obtain the fastest refresh I'm
writing a gtk2 form. I can read a jpeg image from file but I don't
understand how can I create a PGdkPixbuf from an byte array or stream.
The gdk_pixbuf_new_from_stream function does not exists in pfc.

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theo · 2010-05-20 17:07

You could try sth like this:

Code: [Select]  {$ifdef LCLGtk2}
   Cairo, gdk2, gtkDef, gtkProc,
  {$endif}
   Graphics, Classes, SysUtils, opbitmap;


{$ifdef LCLGtk2}
function gdk_cairo_create(drawable: PGdkDrawable): Pcairo_t; cdecl;
external gdklib;

procedure OpBitmapPaint32(Canvas:Graphics.TCanvas; Bmp: TOpBitmap; X,
Y: integer);
var cr: Pcairo_t;
  surface: Pcairo_surface_t;
begin
  Bmp.PixelFormat := pf32bit;
  cr := gdk_cairo_create(TGtkDeviceContext(Canvas.Handle).Drawable);
  surface := cairo_image_surface_create_for_data(Bmp.ScanLine[0],
CAIRO_FORMAT_RGB24, Bmp.Width, Bmp.Height, Bmp.Data.LineLength);
  if surface <> nil then
  begin
    cairo_set_source_surface(cr, surface, X, Y);
    cairo_paint(cr);
  end;
  cairo_destroy(cr);
  cairo_surface_destroy(surface);
end;
{$endif}


Where OpBitmap.ScanLine[0] points to an array of 32bit ARGB.