Hi dear gegl developers :),

I have a proposition to refactor [gegl_]path_calc_values :

static void path_calc_values (GeglPathList *path, + gdouble pos_min, + gdouble pos_max, guint num_samples, gdouble *xs, gdouble *ys)

This modification is consistent with gegl_curve_calc_values which can return a windowed lookup table.
The refactoring merge redundant code (path_calc and path_calc_values). It also fixed what appeared to me as a bug : offset value was just dropped in the 'M' case, which could lead to a noticeable rounding error.

See attached patch : [PATCH] Refactor [gegl_]path_calc_values

* moded gegl/property-types/gegl-path.[c|h] Add pos_min and pos_max parameters to get sample points on an arbitrary portion of the path
This reduces code and should be very useful to extract gegl_path_stroke in a proper operation.

I did not build a test case yet (if anyone has such code and is willing to share, i'd be grateful).

Please review. Regards.

Damien

Another way to go : give a sorted array of positions to compute along the path.

static void path_calc_values_by_position (GeglPathList *path, gdouble *pos_samples, guint num_samples, gdouble *xs, gdouble *ys)

In the case of brush strokes, that would particularly fit spacing dynamics, and other cases which requires computing unevenly distributed points along the path.
It could also be applied to curves

use case : compute_paint_dabs_positions (spacing_curve, n_dabs, dabs_pos); gegl_path_calc_by_pos (path, dabs_pos, n_dabs, xs, ys); gegl_curve_calc_by_pos (size_curve, dabs_pos, n_dabs, dabs_sizes); ...
for (i=0; i
stamp (buffer, stamp_buffer, dabs_pos[i], dabs_sizes[i], ...);

Attached patch obsoletes the previous one.

Regards.

Damien

Patch to add tests for GeglPath, current implementation of gegl_path_calc_values fails.

Damien