Re: embedding arbitrary graphics in text

[Travis Griggs <travisgriggs gmail com>]

On Sep 7, 2010, at 9:15 AM, Behdad Esfahbod wrote:

> Also see pango/examples/cairoshape.c for an example.

OK, I followed it, thank you so much. The only thing that I had to  
look at 3 or so times, before I caught the importance of it, is the  
translate to the cr current point at the top of the render function.  
I'm trying to imagine when I wouldn't want to actually do that.

Question 1

What is the difference between the ink rect and the logical rect. I  
mean, I think I mostly get it. But I'm curious if there are cases  
where portions of the ink would ever lie outside the logical rect? Is  
the "origin (x,y) of the rects always at the baseline of the  
characters, I noticed that they all seem to have negative heights to  
go nominally "upwards". I was curious if there was an example or two  
in the docs somewhere, that showed something I was missing.

Question 2

The example demonstrates how to completely draw something other than  
the font's glyph in place of a character (or more). I'm curious if  
it's possible to still let it draw the character glyphs it was going  
to draw, but do some additional annotation. For example, I'd like to  
insert a stop sign graphic in front of the character run the  
attributes stand for, and nudge them to the right by that much. Or do  
I have to inject filler characters into my text to do that?

What My Binding Ended up Looking Like (for now)

With Behdad's and Tony's direction, I established a single shape  
renderer for any Context I create a binding for in Smalltalk. When I'm  
creating the attribute, I do it with the two rectangles, and with a  
Block Closure. Block Closures are Smalltalk arbitrary functions, that  
close over any current values needed for the function. So I get both  
data and behavior all in one, a lot, or a little. I keep a table on  
the Smalltalk side, which maps Smalltalk blocks, to an arbitrary  
incrementing counter. The index, is what I stuff in the data of the  
attribute. So when I get the callback, I fetch the Smalltalk block  
associated with the particular attribute's data key, execute the block  
with the mapped arguments. Works pretty well.

--
Travis Griggs
Objologist
"The best way to know you have a mind is to change it" -Judge Pierre  
Leval