[fpc-pascal] Implementing AggPas with PtcGraph

[James Richters]

>  * What parameters does its putimage() function take?
>  * Does in support PNG image format natively?

Putimage() takes
Initial X position
Initial Y position
Pointer to beginning of memory bitmap
Method to use (copy, AND, OR, XOR)  
See https://www.freepascal.org/docs-html/rtl/graph/putimage.html


Here's an example:
Var Q: Pointer;
   Bar(0, 0, (GetMaxX div 3), GetMaxY);
   Size := ImageSize(10, 20, 30, 40);
   GetMem(Q, Size);   { Allocate memory on heap }
   GetImage(10, 20, 30, 40, Q^);
   Readln;
   ClearDevice;
   PutImage(100, 100, Q^, NormalPut);
   readln;
   putimage(0,0,Q^,normalput);
   readln;

I can get this to work with getimage and putimage, but I have no idea how to build the image in memory and just use putimage.

I don't think it really supports any 'image formats'  it's just the TP compatible graphics thing for DOS style graphics.

I'm looking at it and I think getimage / putimage are just one byte per pixel... maybe?  so probably not what I want. 
I'm getting the feeling this is apples and oranges here, TP compatible memory map vs tcolor or tfpcolor or some other scheme with 4 bytes per pixel.
Maybe there just isn't anything canned that can do what I want?  Maybe I need to put the pixels on the screen myself using a nested loop and getpixel / putpixel and do whatever logic on my own.

James

-----Original Message-----
From: fpc-pascal [mailto:fpc-pascal-bounces at lists.freepascal.org] On Behalf Of Graeme Geldenhuys
Sent: Tuesday, May 30, 2017 4:55 PM
To: fpc-pascal at lists.freepascal.org
Subject: Re: [fpc-pascal] Implementing AggPas with PtcGraph

On 2017-05-30 20:20, James Richters wrote:
> I've re-attached Graeme's sample slightly modified to open the 
> ptcgraph window, and attempt to use putimage on line 103 but when I 
> run it I get 217- access violation

I haven't downloaded or looked at ptcgraph at all. A few questions:

  * What parameters does its putimage() function take?
  * Does in support PNG image format natively?

I would imagine that it probably supports BMP only - comping from DOS and Windows background. If so, change the example program to use a BMP image instead of a PNG image. In your code you attached you are actually pushing the c variable, which is a TFPColor record of the last color retrieve from the AggPas buffer - so no surprise you are getting a AV error.

Regards,
   Graeme

--
fpGUI Toolkit - a cross-platform GUI toolkit using Free Pascal http://fpgui.sourceforge.net/

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