Bitmap-Ausschnitt einfärben

[stahli]

Ja, AlphaBlend passt gut.

Für den Fall, dass jemand in dem Bereich Infos sucht, hier der aktuelle Stand:

Delphi-Quellcode:

  procedure UnderMouseEffectDrawTransp;
  var
    tmpBitmap: TBitmap;
  begin
    tmpBitmap := TBitmap.Create;
    tmpBitmap.Width := ClientRect.Width;
    tmpBitmap.Height := ClientRect.Height;
    tmpBitmap.Canvas.Brush.Style := bsDiagCross;
    tmpBitmap.Canvas.Brush.Color := clWhite;
    tmpBitmap.Canvas.FillRect(TRect.Create(0, 0, tmpBitmap.Width,
      tmpBitmap.Height));
    // tmpBitmap.SaveToFile('xxx.bmp');
    DrawTransparentBitmap(tmpBitmap, aBitmap.Canvas, ClientRect, $07);
    // aBitmap.Canvas.Brush.Color := clYellow;
    // aBitmap.Canvas.FillRect(aRect);
    // SetStretchBltMode(aBitmap.Canvas.Handle, COLORONCOLOR);
    // StretchBlt(aBitmap.Canvas.Handle, ClientRect.Left, ClientRect.Top,
    // ClientRect.Width, ClientRect.Height, tmpBitmap.Canvas.Handle, 0, 0,
    // tmpBitmap.Width, tmpBitmap.Height, SRCCOPY);
    // aBitmap.Canvas.CopyMode := cmWhiteness;
    // aBitmap.Canvas.CopyRect(ClientRect, tmpBitmap.Canvas,
    // tmpBitmap.Canvas.ClipRect);
    tmpBitmap.Free;
  end;

  procedure MouseDownEffectDrawTransp;
  var
    tmpBitmap: TBitmap;
  begin
    tmpBitmap := TBitmap.Create;
    tmpBitmap.Width := ClientRect.Width;
    tmpBitmap.Height := ClientRect.Height;
    tmpBitmap.Canvas.Brush.Style := bsDiagCross;
    tmpBitmap.Canvas.Brush.Color := clWhite;
    tmpBitmap.Canvas.FillRect(TRect.Create(0, 0, tmpBitmap.Width,
      tmpBitmap.Height));
    // tmpBitmap.SaveToFile('xxx.bmp');
    DrawTransparentBitmap(tmpBitmap, aBitmap.Canvas, ClientRect, $10);
    // aBitmap.Canvas.Brush.Color := clYellow;
    // aBitmap.Canvas.FillRect(aRect);
    // SetStretchBltMode(aBitmap.Canvas.Handle, COLORONCOLOR);
    // StretchBlt(aBitmap.Canvas.Handle, ClientRect.Left, ClientRect.Top,
    // ClientRect.Width, ClientRect.Height, tmpBitmap.Canvas.Handle, 0, 0,
    // tmpBitmap.Width, tmpBitmap.Height, SRCCOPY);
    // aBitmap.Canvas.CopyMode := cmWhiteness;
    // aBitmap.Canvas.CopyRect(ClientRect, tmpBitmap.Canvas,
    // tmpBitmap.Canvas.ClipRect);
    tmpBitmap.Free;
  end;

  function Clamp(Value: Integer; Min, Max: Integer): Byte; inline;
  begin
    Result := Value;
    if Result < Min then
      Result := Min;
    if Result > Max then
      Result := Max;
  end;

  procedure AdjustLuminance(Bmp: TBitmap; Offset: SmallInt);
  var
    // Bmp: TBitmap;
    Pixel: PRGBQuad;
    X, Y: Integer;
  begin
    Bmp.PixelFormat := pf32Bit;
    for Y := ClientRect.Top to ClientRect.Bottom do
    begin
      // Pointer auf 1. Pixel in der Zeile holen
      Pixel := Bmp.Scanline[Y];
      System.Inc(Pixel, ClientRect.Left);
      for X := ClientRect.Left to ClientRect.Right do
      begin
        Pixel^.rgbRed := Clamp(Integer(Pixel^.rgbRed) + Offset, 0, 255);
        Pixel^.rgbGreen := Clamp(Integer(Pixel^.rgbGreen) + Offset, 0, 255);
        Pixel^.rgbBlue := Clamp(Integer(Pixel^.rgbBlue) + Offset, 0, 255);

        // ein Pixel nach rechts gehen
        System.Inc(Pixel);
      end;
    end;
  end;

  procedure UnderMouseEffectLumi;
  begin
    AdjustLuminance(aBitmap, -2); // Abdunkeln
  end;

  procedure MouseDownEffectLumi;
  begin
    AdjustLuminance(aBitmap, -5); // Abdunkeln
  end;

  procedure UnderMouseEffectAlpha;
  var
    tmpBitmap: TBitmap;
    BlendFunc: TBlendFunction;
  begin
    tmpBitmap := TBitmap.Create;
    tmpBitmap.Width := ClientRect.Width;
    tmpBitmap.Height := ClientRect.Height;
    tmpBitmap.Canvas.Brush.Color := clHighlight;
    tmpBitmap.Canvas.FillRect(Rect(0, 0, tmpBitmap.Width, tmpBitmap.Height));

    // Blend a foreground image over the top - constant alpha, not per-pixel
    BlendFunc.BlendOp := AC_SRC_OVER;
    BlendFunc.BlendFlags := 0;
    BlendFunc.SourceConstantAlpha := 5;
    BlendFunc.AlphaFormat := 0;
    AlphaBlend(aBitmap.Canvas.Handle, ClientRect.Left, ClientRect.Top,
      tmpBitmap.Width, tmpBitmap.Height, tmpBitmap.Canvas.Handle, 0, 0,
      tmpBitmap.Width, tmpBitmap.Height, BlendFunc);

    tmpBitmap.Free;
  end;

  procedure MouseDownEffectAlpha;
  var
    tmpBitmap: TBitmap;
    BlendFunc: TBlendFunction;
  begin
    tmpBitmap := TBitmap.Create;
    tmpBitmap.Width := ClientRect.Width;
    tmpBitmap.Height := ClientRect.Height;
    tmpBitmap.Canvas.Brush.Color := clHighlight;
    tmpBitmap.Canvas.FillRect(Rect(0, 0, tmpBitmap.Width, tmpBitmap.Height));

    // Blend a foreground image over the top - constant alpha, not per-pixel
    BlendFunc.BlendOp := AC_SRC_OVER;
    BlendFunc.BlendFlags := 0;
    BlendFunc.SourceConstantAlpha := 20;
    BlendFunc.AlphaFormat := 0;
    AlphaBlend(aBitmap.Canvas.Handle, ClientRect.Left, ClientRect.Top,
      tmpBitmap.Width, tmpBitmap.Height, tmpBitmap.Canvas.Handle, 0, 0,
      tmpBitmap.Width, tmpBitmap.Height, BlendFunc);

    tmpBitmap.Free;
  end;

@Namenloser: Brachte keine Besserung (für mich jetzt auch nicht dringend).