[SOLVED]How to save multiple controls into one image file?
lazarus / 39-Graphics

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CM630 · 2013-05-10 06:45

I need to save several TAcharts into one image file. They shall be
placed one to another as they are placed in  the frame (sometimes
their total height might be greater than the height of the screen). I
hope there is an easy solution?
Merging (adding) several images into one might b okay for me, since
all the TACharts are one under another and they have equal dimensions.
Separate TACharts are exported easily- Chart.SaveToBitmap(..)

EDIT: So far I did things with ImageMagick: convert -append
SourceImage1.bmp SourceImage2.bmp SourceImage3.bmp .....
TargetImage.bmp but I'd prefer a more native way?

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wp · 2013-05-14 07:26

Find the total height and maximum width of your charts.Create a bitmap
and set its size accordingly.For each chart: create a temporary bitmap
by calling SaveToImage(TBitmap), draw it onto the canvas of the total
bitmap in the correct vertical position, free the temporary
bitmap.Save the total bitmap to file, use standard bitmap techniques
for file format conversion.
This works for two charts:
Code: [Select]procedure TForm1.SaveTwoCharts(AFileName: String);
var
  w,h: Integer;
  y : Integer;
  bmp: TBitmap;
  img: TRasterImage;
begin
  w := max(Chart1.Width, Chart2.Width);
  h := Chart1.Height + Chart2.Height;

  bmp := TBitmap.Create;
  try
    bmp.SetSize(w, h);
    y := 0;
    img := Chart1.SaveToImage(TBitmap);
    try
      bmp.Canvas.Draw(0, y, img);
      y := y + Chart1.Height;
    finally
      img.Free;
    end;
    img := Chart2.SaveToImage(TBitmap);
    try
      bmp.Canvas.Draw(0, y, img);
    finally
      img.Free;
    end;
    bmp.SaveToFile(AFileName);
  finally
    bmp.Free;
  end;
end;

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CM630 · 2013-05-17 11:06

Thanks, it's perfect!