The width is always in hires pixels!
The resolution (Hires/Lowres) will be what was used for the original picture. That's the one used to define the graphic elements, lines and boxes used in Interface programs.
So, if the original piccie is Hires, the Width parameter will be in Hires pixels. If it was Lowres, the Width parameter will be in Lowres pixels.
The Limit Mouse bug for Resource Screen Open is not related to the Limit Mouse instruction. What happens is, after a Resource Screen Open (Hires source picture
or Lowres source picture) the mouse is trapped to the height of the Default screen no matter what you set for the Height parameter.
If AMOS Pro is installed on a PAL system, the Default screen height is set to 200 lines in Lowres. So opening a resource screen 256 lines high sees the mouse trapped to the top 200 lines.
An easy fix is to set up the Default screen properly in the Editor's Config menu. It's on the page 1 option button (from memory, I haven't got WINUAE and AMOS open while I write this). Setting the Default Screen Size and Position also affects the Editor display. So it's also well worthwhile if you find your Editor's display isn't positioned correctly on your screen.
That fixes the problem permanently, but it's not a programmatic solution. So I see it as a bug
I now use the Default Screen's hardware offsets to set up any screen in my code. That way the screen will always be positioned perfectly for the user's setup (assuming they
have set it up!). The example below is from the DBL Editor code and opens a Resource Screen. But it works for any screen:
'
' Offsets from Screen Base address:
'
GC_EC_WX=$52 : Rem X display offset
GC_EC_WY=$54 : Rem Y display offset (in low byte)
...
...
Auto View Off
' Grab the display offsets from the default screen;
Default
A=Screen Base
G_XPOS=Deek(A+GC_EC_WX)
G_YPOS=Deek(A+GC_EC_WY) and $FF
Resource Screen Open 0,640,G_YSIZE,0
Screen Display 0,G_XPOS,G_YPOS,640,G_YSIZE
Auto View On
Wait Vbl