ShrimpWorks

More a curiosity than an actual useful project, I just had an Idea I wanted to try out, and this is the result.

This Java application (or library, if you want to include it in your own project) simply takes a source image, a couple of optional parameters, and outputs a new image with a halftone- like effect.

Briefly, works by stepping through the pixels of the source image at an interval defined by the dot size specified, samples the brightness of that pixel, and draws a circle onto the destination image, scaled according to the source pixel brightness.

For reference, take a look at the java.awt Graphics2D, Image and BufferenImage classes. It’s really nice to half a whole bunch of image processing and drawing capabilities available within the standard library, rather than needing to rely on external things (as I recently discovered to be the case with Ruby - pretty much all image processing is done via an ImageMagick dependency).

The source, documentation and a download are available from the image-halftone GitHub project page.

I’ve had to do quite a bit of stuff with images in Delphi recently (lots of manual drawing too), and discovered TCanvas’ TextOut method will only draw text onto one line, line breaks and newlines are ignored. Google search results suggested Windows’ DrawText function, however despite all the formatting and alignment flags it takes, it refused to draw text centred vertically.

Anyway, here’s a small-ish procedure which will take your multi-line text, and draw it centred on the canvas you pass it. You also need to pass the width and height of the canvas you’re drawing to. It assumes the font can everything else has been set by you, prior to calling it. Also, be sure “Graphics” is in your “uses” section.

procedure multilineCanvasText(canvas: TCanvas; text: String; width, height: Integer);
var
  textSize: TSize;
  lines: TStringList;
  i, blockHeight: Integer;
begin
  // lazy man's way of splitting text by line into a list (split by #13#10)
  lines := TStringList.Create;
  lines.Text := text;

  // see how high our block of text is going to be, based on the font the canvas
  // currently has set
  textSize := canvas.TextExtent('LOZL!');
  blockHeight := textSize.cy * lines.Count;
  blockHeight := blockHeight;

  // go through each line and output it
  for i := 0 to lines.Count - 1 do
  begin
    // we need the width of each line, so we can center it on the canvas
    textSize := canvas.TextExtent(lines[i]);
    // render the text
    canvas.TextOut((width div 2) - (textSize.cx div 2),
                   (height div 2) - (blockHeight div 2) + (textSize.cy * i),
                   lines[i]);
  end;
  freeAndNull(lines);
end;