Paintbox image conversion to a bitmap file 2

[stylonurus]

I am writing a program which displays waveforms on a form. Actually I use two Paintboxes to display 8 waveforms.

The waveforms come to me via the internet from another program I wrote previously.

To display the waveforms I use a lot of Ref->Canvas->LineTo calls where Ref is the TPaintBox *

Now I would like to be able to save these waveforms as either .jpg or .gif. I searched this forum but either my search criteria sucks or its so easy nobody would bother to ask. But it's not so easy for me. I am definitely not a Builder or Graphics power user and so

Any helpful insights on how to get started would be very welcome at this time.

Thanks

Rick

 

[2ffat]

See if this has some source code you can use:

http://www.codeproject.com/bitmap/cximage.asp

It says it can be used with Borland compilers. Maybe if you sift through the code you can figure something out.


James P. Cottingham
-----------------------------------------
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I'm number 1,229![/sup]

 

[stylonurus]

2ffat, Thanks for the link to this very interesting site.

Still I think I should be able to save a waveform created in a paintbox to a gif, bmp or jpg file using the Borland Builder C++ library.

I actually found a simple example that creates . bmp file using the following

Graphics::TBitmap* bm = new Graphics::TBitmap;
tmpW=Chart1->Width;
tmpH=Chart1->Height;

Chart1->Draw(bm->Canvas,Rect(tmpW+1,tmpH+1,2*tmpW,2*tmpH));
Chart1->BufferedDisplay=true;
bm->SaveToFile("C:\\bit.bmp");

Unfortunately the Paintbox does not have a Draw method and the PaintBox->Canvas->Draw I have not yet got to work.

Thanks for your reply. I appreciate it.

Rick

 

[tsh73]

ok, I'm long forget all this stuff - but I got something work.
Probably it will help you.
Ok:
I have a PaintBox1 , on which I draw with lineTo:
Form3->PaintBox1->Canvas->LineTo(200,200);

Now I have Image1 (you probably can make it hidden?)
and on a button "Save" I do the code:

Form3->Image1->Canvas->CopyRect(
	Rect(0,0,Form3->PaintBox1->Width,Form3->PaintBox1->Height),
	PaintBox1->Canvas,
	Rect(0,0,Form3->PaintBox1->Width,Form3->PaintBox1->Height));
Form3->Image1->Picture->SaveToFile("C:\\bit.bmp");

of cource there something should be done to match size of Image (to be saved) with sice of PaintBox - but it works, I'got an image file on disk! )

 

[stylonurus]

tsh73,
Thanks for your reply. I actually tried something like this, gave up as I headed into another direction...I think it was close to what you did but I could not get it to work. I am going to try your method later today and will get back to you.. (I'm traveling today so time is limited)...

I actually ended up using a teechart or TChart. It has a built in Draw method that works. Here is some of their demo code that I used to save the Chart on a button press.

// save waveform
void __fastcall TForm3::Button2Click(TObject *Sender)
{
  Graphics::TBitmap *    bm = new Graphics::TBitmap;
  int                    tmpH,tmpW;
 
  tmpW=Chart1->Width;
  tmpH=Chart1->Height;
  bm->Width = 2*tmpW;
  bm->Height= 2*tmpH;
   
  // create chart etc;
 
  // draw chart 1  and save it to disk
  Chart1->Draw(bm->Canvas,Rect(0,0,tmpW,tmpH));
  Chart1->BufferedDisplay=true;
  bm->SaveToFile("C:\\bit2.bmp");

}

I am really impressed with this TChart although I had to spend hours with trial and error to understand a small part of the many many options it offers.

 

[stylonurus]

tsh73,
I was able to spend some time looking into this working piece of code. More often than not, I can get a better understanding of how a method works by seeing a working example. In the example you gave which I listed below I believe that the Canvas of Image1 will be updated from the canvas of the PaintBox. I noticed that the sizes of the rectangle coordinates are equal. Must they be? If I increase the rectangle size of the destination the resulting .bmp file is distorted. When they are equal it is perfect. Also I thought I could change the source canvas from paintbox to Form3->Canvas (which would capture all the objects visible on it). When I do this I only get some outlining labels and a few lines. In any event I really appreciate the example and given the time I will experiment more to better understand the CopyRect function. Thanks

Rick

Form3->Image1->Canvas->CopyRect(
    Rect(0,0,Form3->PaintBox1->Width,Form3->PaintBox1->Height),
    PaintBox1->Canvas,
    Rect(0,0,Form3->PaintBox1->Width,Form3->PaintBox1->Height));
Form3->Image1->Picture->SaveToFile("C:\\bit.bmp");