textstyle_getwidth--humppake: How to get valid text widths in AWT

Author: Benja Fallenstein
Author: Asko Soukka
Date: 2002-11-26
Revision: 1.2
Status: Irrelevant
<benja> in AWT, we need to do all the font-related calculations 
        in screen coordinates (pixels)
<benja> so, we first need to transform local coordinates 
        into screen coordinates
<benja> then we can calculate the scale correctly

<benja> not only do we have to encapsulate getting the scale
<benja> but also getting the width
<benja> that can go into TextStyle


We ran into problem with TextCellContentView. We got proper scrolling and correctly placed cursor vob in AWT, only after a few ugly explicit transformations:

<benja> actually, we first need to calculate the text width 
        in screen coordinates
<benja> and then convert *that* to local 

<benja> the problem is the difference between screen 
        coordinates and coordinates inside the box coordinate 
<benja> (or should I say: The problem is the difference 
        between the screen and the box coordinate system)
<humppake> benja: And why it is not a problem with GL?
<benja> humppake, because of the difference in how 
        getScaleByHeight works, I think
<benja> humppake, the main difference between AWT and GL here
        is that GL has arbitrarily scalable fonts


Is there any way to make AWTTextStyle scale virtually arbitrarily like GLTextStyle?

Would it be enough to fix our problem (with TextCellContentView for example)?

If not, which would be the best of the following alternatives as the new interface?


One special method

<benja> why not simply float getWidthForHeight(VobCoorder 
        coorder, int cs, String s, float height)?

<benja> so that we can provide an AWT-specific 
        impl in AWTTextStyle
<benja> what we need to get is: the width of the text inside a 
        given coordsys, if the height of the text in that 
        coordsys is X
<benja> however, you can have a rather simple implementation
        for GL
<benja> which doesn't actually look at the cs, probably

Stack of CSs

<humppake> benja: I mean, if we give TextStyle a CS before
        calling getFunctions, it will use that CS to transform 
        the results.
<humppake> benja: It lasts only for one call O:-)
<benja> I don't know. It could be a possibility, if we find 
        good definitions for all the methods