Eliminate accidental trigraphs

Those particular instances were harmless, but in general trigraphs can
cause unintended behaviour changes. Not having any trigraphs in the code
makes it easier to catch unintended ones via a simple regex.
(In GNU-C trigraphs are disabled by default, but enabled in ISO-C)

1 files changed, 3 insertions, 3 deletions

diff --git a/libass/ass_render.c b/libass/ass_render.c
index eaf135b..9498a18 100644
--- a/libass/ass_render.c
+++ b/libass/ass_render.c
@@ -511,7 +511,7 @@ static bool quantize_transform(double m[3][3], ASS_Vector *pos,
     //  = m_zx * (x + sign(m_zx) * dx) + m_zy * (y + sign(m_zy) * dy) + z0.
 
     // D(f)--absolute value of error in quantity f
-    // as function of error in matrix coefficients, i. e. D(m_??).
+    // as function of error in matrix coefficients, i. e. D(m_ij) for i, j from {x, y, z}.
     // Error in constant is zero, i. e. D(dx) = D(dy) = D(z0) = 0.
     // In the following calculation errors are considered small
     // and second- and higher-order terms are dropped.
@@ -536,7 +536,7 @@ static bool quantize_transform(double m[3][3], ASS_Vector *pos,
 
     // To estimate acceptable error in matrix coefficient
     // set error in all other coefficients to zero and solve system
-    // D(x_out) <= ACCURACY & D(y_out) <= ACCURACY for desired D(m_??).
+    // D(x_out) <= ACCURACY & D(y_out) <= ACCURACY for desired D(m_ij).
     // ACCURACY here is some part of total error, i. e. ACCURACY ~ POSITION_PRECISION.
     // Note that POSITION_PRECISION isn't total error, it's convenient constant.
     // True error can be up to several POSITION_PRECISION.
@@ -1400,7 +1400,7 @@ get_bitmap_glyph(ASS_Renderer *render_priv, GlyphInfo *info,
 
         // Notation from quantize_transform().
         // Note that goal here is to estimate acceptable error for stroking, i. e. D(x) and D(y).
-        // Matrix coefficients are constants now, so D(m_??) = 0.
+        // Matrix coefficients are constants now, so D(m_ij) = 0 for all i, j from {x, y, z}.
 
         // D(z) <= |m_zx| * D(x) + |m_zy| * D(y),
         // D(x_out) = D((m_xx * x + m_xy * y) / z)