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author | Matthias Clasen <mclasen@redhat.com> | 2021-09-11 12:30:46 -0400 |
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committer | Matthias Clasen <mclasen@redhat.com> | 2022-01-02 13:33:37 -0500 |
commit | 492df836ade5056e73f4779593ce31598ed77d85 (patch) | |
tree | a22e6c13b3b1c14568c306443323d51b63400231 /pango | |
parent | fc46f12754e9035c71da2747be55361ddfcf7635 (diff) | |
download | pango-492df836ade5056e73f4779593ce31598ed77d85.tar.gz |
Add pango_matrix_get_slant_ratio
Add API to extract the slant ratio from a PangoMatrix.
Tests included.
Diffstat (limited to 'pango')
-rw-r--r-- | pango/pango-matrix.c | 34 | ||||
-rw-r--r-- | pango/pango-matrix.h | 2 |
2 files changed, 36 insertions, 0 deletions
diff --git a/pango/pango-matrix.c b/pango/pango-matrix.c index a066eb57..3bc0ff16 100644 --- a/pango/pango-matrix.c +++ b/pango/pango-matrix.c @@ -263,6 +263,40 @@ pango_matrix_get_font_scale_factors (const PangoMatrix *matrix, } /** + * pango_matrix_get_slant_ratio: + * @matrix: a `PangoMatrix` + * + * Gets the slant ratio of a matrix. + * + * For a simple shear matrix in the form: + * + * 1 λ + * 0 1 + * + * this is simply λ. + * + * Returns: the slant ratio of @matrix + * + * Since: 1.50 + */ +double +pango_matrix_get_slant_ratio (const PangoMatrix *matrix) +{ + double x0, y0; + double x1, y1; + + x0 = 0; + y0 = 1; + pango_matrix_transform_distance (matrix, &x0, &y0); + + x1 = 1; + y1 = 0; + pango_matrix_transform_distance (matrix, &x1, &y1); + + return (x0 * x1 + y0 * y1) / (x0 * x0 + y0 * y0); +} + +/** * pango_matrix_transform_distance: * @matrix: (nullable): a `PangoMatrix` * @dx: (inout): in/out X component of a distance vector diff --git a/pango/pango-matrix.h b/pango/pango-matrix.h index d4277401..cb53a422 100644 --- a/pango/pango-matrix.h +++ b/pango/pango-matrix.h @@ -121,6 +121,8 @@ double pango_matrix_get_font_scale_factor (const PangoMatrix *matrix) G_GNUC_PUR PANGO_AVAILABLE_IN_1_38 void pango_matrix_get_font_scale_factors (const PangoMatrix *matrix, double *xscale, double *yscale); +PANGO_AVAILABLE_IN_1_50 +double pango_matrix_get_slant_ratio (const PangoMatrix *matrix) G_GNUC_PURE; G_END_DECLS |