Add missing cairo-svg dependency to test-ot-color

[jameshilliard]

Should fix:

test-ot-color.cc:40:10: fatal error: cairo-svg.h: No such file or directory
   40 | #include <cairo-svg.h>
      |          ^~~~~~~~~~~~~

[behdad]

I don't like configure check for this. @ebraminio can you change to just use cairo PNG backend instead? Or use #ifdefs. That's what hb-view does.

[jameshilliard]

cairo PNG would still require a dependency check for this right?

[behdad]

The cairo PNG backend is always buillt in, so we don't check extra for hb-view and never had any complaints.

These are macros to check for all:

helper-cairo.cc:  #ifdef CAIRO_HAS_PS_SURFACE
helper-cairo.cc:#ifdef CAIRO_HAS_PNG_FUNCTIONS
helper-cairo.cc:  #ifdef CAIRO_HAS_PNG_FUNCTIONS
helper-cairo.cc:  #ifdef CAIRO_HAS_SVG_SURFACE
helper-cairo.cc:  #ifdef CAIRO_HAS_PDF_SURFACE
helper-cairo.cc:  #ifdef CAIRO_HAS_PS_SURFACE

[jameshilliard]

The cairo PNG backend is always buillt in

Are you sure? What about when cairo is built with --disable-png?

[behdad]

You're right. The image backend is always built in, but the PNG functions can be disabled. At any rate, I don't like adding extra checks just for test-ot-colors. The test file can just not save to anything if the necessary cairo features are not available.

[jameshilliard]

Updated to use the CAIRO_HAS_SVG_SURFACE macro instead.

[ebraminio]

Hey there, shouldn't cairo header itself be included before checking its definitions?

[jameshilliard]

updated, hopefully that works

[ebraminio]

Merged, thanks for your contribution :)