| Author |
 Topic  |
|
|
agnes
USA
2 Posts |
 Posted - May 25 2013 : 18:48:29
|
Hi,
I am trying to figure out the following...
I have a bitmap that will be zoomed larger than its ImageEnView1 component. Now, whereever I pan the image to, I would like to zoom in and out (with a button/code) without the current TopLeft pixel moving. I would expect it to move when zooming smaller than the component would allow for. Thanks.
--Aggie |
|
|
fab
1310 Posts |
Posted - May 27 2013 : 13:13:48
|
Hi,
ImageEn "direct" the zoom at the center.
You may change this, scrolling to the pixel you want to display, just after setting zoom. Example:
ImageEnVect1.Zoom := ....;
ImageEnView1.ViewX := 0;
ImageEnView1.ViewY := 0;
You could also set ImageEnView1.Center=false (this is not an alternative way).
|
 |
|
|
agnes
USA
2 Posts |
Posted - May 29 2013 : 20:33:13
|
fab,
Thanks for pointing me in the right direction. Here is what I came up with. Works well with 50%, 100%, 200%, etc.
//--------------------------------------------------------------------
procedure TForm1.ZoomFromTopLeft(AImage: TImageEnVect; AZoom: double);
var
newViewX, newViewY : integer ;
begin
with AImage do
begin
newViewX := Trunc(AZoom / Zoom * ViewX);
newViewY := Trunc(AZoom / Zoom * ViewY);
Perform(WM_SETREDRAW, 0, 0);
Zoom := AZoom;
ViewX := newViewX;
ViewY := newViewY;
Perform(WM_SETREDRAW, 1, 0);
Invalidate;
end;
end;
//--------------------------------------------------------------------
I was ready to tear my hair out trying to find a bitmap point, screen point, client point -- that could be plugged into the ZoomAt procedure. FYI, my project is for viewing census scans, and needs to remain at the same line/column when zooming. Thanks again!
|
|
|
| |
Topic |
|
|
|
Search
Zooming with fixed TopLeft pixel?
