Text does not appear with Cairo on Windows.

[fryguybob]

(Imported from http://code.google.com/p/diagrams/issues/detail?id=36. Original issue from fryguy...@gmail.com on June 15, 2011, 03:17:52 PM UTC)

It appears that there is a serious bug in Cairo that prevents text from showing on Windows when showing text is proceeded by a call to transform the current transform matrix. moveTo, rotate, and scale calls all appear to work as expected.

Different versions of Cairo behave differently:

• Version 1.8.10 (gtk 2.20 all-in-one bundle) as described above.
• Version 1.10.2 (gtk 2.22 all-in-one bundle) fails with error: user error (invalid matrix (not invertible)) This is the error CAIRO_STATUS_INVALID_MATRIX. The reason for this difference appears to be related to this change.
• Version 1.11.3 (Current head built locally). This build did not use freetype and that may explain the differences. Text did show, but when using a matrix transformation, it was clipped strangely ("hello world" was missing the 'h').

While this is not an issue with Diagrams directly I'm documenting here to keep track of things. The following code reproduces the issue:

import qualified Graphics.Rendering.Cairo as C
import qualified Graphics.Rendering.Cairo.Matrix as CM

main = C.withPSSurface "t.ps" 500 500 surfaceF
  where
    surfaceF s = C.renderWith s r'
    r' = do
      C.moveTo 100 100
      -- C.transform $ CM.Matrix 1.0 0.0 0.0 1.0 0.0 100.0 -- no text.
      -- C.transform $ CM.Matrix 1.0 0.0 0.0 1.0 0.0 0.0   -- works.
      C.translate 0.0 100.0 -- works
      C.showText "hello world"

[bergey]

This is likely fixed by https://github.com/diagrams/diagrams-cairo/commit/b953ae90d3c1ba13c15bc5a86c5fa4851da16ce7. Can someone on windows test? I'll fire up a VM in a few days, if no one gets to it sooner.