Delphi Multimedia Methods

• see also:
  • Delphi Programming Main Index

Writing to a form's canvas - color triangles, etc. DI Aug 1995

Displaying a video on a panel:

• MediaPlayer.DisplayRect := Panel1.clientRect;

Play a wav file:

• sndPlaySound('wavefile.wav',snd_Sync);
  • nb. use snd_Sync if wish to halt program whilst sound being played otherwise use snd_ASync.
  • nb. must have MMSystem in uses clause;

Colors:

• TColor is a 4 byte LongInt, the 1st byte determines how the color is rendered on screen, the next 3 bytes represent blue, green & red respectively:
  • eg. $0200FF00 = green, $02FF0000 = blue, $020000FF = red ($FF=255), $02000000 = black, $02FFFFFF = white;

Random colors: (see Delphi Informant Aug,96 pp52..)

• Randomize; {need to set this once for the program}
• form1.color := $02000000 + Trunc($FFFFFF * Random);
• NB. can also do this to fill a form with random colors:
  • var x, y: integer;
  • begin
  • for x := 0 to Form1.ClientWidth do
    • for y := 0 to Form1.ClientHeight do
      • Form1.canvas.pixels[x,y] := the above
  • end;

Tiling a bitmap on a form:

• Form.OnPaint event:
  • var xPos, yPos, bmpWidth, bmpHeight: LongInt;
  • begin with myBitmap do
    • begin bmpWidth := Width; bmpHeight := Height; end;
    • ypos := 0;
    • while yPos < Height do
      • begin
      • xPos := 0;
      • while xPos < width do
        • begin
        • Canvas.draw(xpos,ypos,myBitmap);
        • xpos := xpos + bmpWidth;
        • end;
      • yPos := yPos + bmpHeight;
      • end;
  • end;
• Form.OnCreate event:
  • begin
  • try myBitmap := TBitmap.create;
  • myBitmap.LoadFromFile(imagefile);//should be 40x40pixels in size preferably
  • except myBitmap.free; end;
  • end;