[Gambas-user] an "Is this possible question" about images

[richard terry]

On Friday 15 April 2011 16:15:13 Kevin Fishburne wrote:
Thanks, and to  Rolf-Werner Eilert's reply, I'll take a look at these 
suggestions when I go home.

I need a little 'side project' to stave off the bordum of the hum-drum 
debugging of the main project.

Will post back my  sucess or lack therof 

Regards

Richard

> On 04/15/2011 12:47 AM, richard terry wrote:
> >> Do you need it to look like a fisheye-style lens effect, or just
> >> box-zoom an area? If the latter this can be done easily in gb code.
> >
> > Just the box-zoom .
> >
> > Any change of you giving me a helping hand? I've not done anything much
> > with images or drawing.
> >
> > I'll mail you a sample png if you want - the purpose here is to magnify
> > areas of either skin, xray films or dermatascope images - all are images
> > at the end of the day.
> >
> > Its for our open - source medical records project that Ian and I are
> > chuggling slowly along with - not releasable as yet by I'm hoping that by
> > the end of 2011 it will be pretty much beta.
> 
> That is very cool. I'm doing a game so I know a little about images in gb.
> 
> I'm going to assume that you're using Qt or GTK and not SDL or OpenGL,
> but correct me if I'm wrong. For those the easiest way to do graphics is
> with a DrawingArea control. After creating it on the form I'd change the
> Cached property to True so it will automatically redraw itself if
> something moves over it.
> 
> You create image variables and load image files into them like this:
> 
> Dim/Public someimage As Image
> someimage = Image.Load("FleshEatingVirusNooooo.jpg")
> 
> You write images to the DrawingArea control like this:
> 
> Draw.Begin(DrawingArea1)
>    Draw.Image(someimage, X, Y, [Width, Height, SrcX, SrcY, SrcWidth,
> SrcHeight])
>    ' Add more "Draw.Image" statements here to composite additional
> images into the DrawingArea.
> Draw.End ' Commits the composition to the DrawingArea so that it may be
> seen. May need a "Wait" statement if done repeatedly.
> 
> The [bracketed] parameters are optional. someimage is the source and the
> DrawingArea is the target. You can specify a subset of the source (the
> area to be zoomed) by playing with SrcX and SrcY (upper-left corner of
> source to be drawn) and SrcWidth and SrcHeight (width and height
> relative to SrcX and SrcY of source to be drawn). You can scale the
> source by playing with Width and Height.
> 
> So that the source image writes to the DrawingArea don't leave a trail,
> I'd first draw the main (unzoomed) image to the DrawingArea, then draw
> the zoomed area onto that for each "frame" that you draw. The logic
> would go something like:
> 
> ' Create your image variables.
> ' Load images into your image variables.
> Draw.Begin(DrawingAreaControlName)
> ' Draw the main image into the DrawingArea.
> ' Draw part of the main image into the DrawingArea adjusted by cursor
> position, zoom area size and zoom level.
> ' Draw text or whatever else you need to into the DrawingArea.
> Draw.End
> 
> To draw text, which is really cool, you may do something like this
> inside the Draw.Begin/End:
> 
> Draw.Foreground = Color.Black
> Draw.Text("Look, it's text on an image with a crappy shadow!!!", X, Y)
> Draw.Foreground = Color.White
> Draw.Text("Look, it's text on an image with a crappy shadow!!!", X + 1,
> Y - 1)
> 
> I don't have any project examples that are simple enough to demonstrate
> this, but if you're really having trouble I could put something together.
>