From b634beb39e0a4fef7167a8af646f6b2d8cafe69b Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Thu, 20 May 2010 17:44:52 +0100
Subject: [PATCH] Fix delta scale, again...

---
 src/hb-ot-layout-common-private.hh |  8 ++++++++
 src/hb-ot-layout-gdef-private.hh   |  3 +--
 src/hb-ot-layout-gpos-private.hh   | 12 ++++++------
 src/hb-ot-layout-private.hh        |  2 +-
 4 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index e054b5935..f96549143 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -566,6 +566,14 @@ struct ClassDef
 
 struct Device
 {
+  /* XXX speed up */
+
+  inline hb_position_t get_x_delta (hb_ot_layout_context_t *c) const
+  { return c->font->x_ppem ? get_delta (c->font->x_ppem) * (uint64_t) c->font->x_scale / c->font->x_ppem : 0; }
+
+  inline hb_position_t get_y_delta (hb_ot_layout_context_t *c) const
+  { return c->font->y_ppem ? get_delta (c->font->y_ppem) * (uint64_t) c->font->y_scale / c->font->y_ppem : 0; }
+
   inline int get_delta (unsigned int ppem_size) const
   {
     unsigned int f = deltaFormat;
diff --git a/src/hb-ot-layout-gdef-private.hh b/src/hb-ot-layout-gdef-private.hh
index 4989363a0..1adff6e48 100644
--- a/src/hb-ot-layout-gdef-private.hh
+++ b/src/hb-ot-layout-gdef-private.hh
@@ -144,8 +144,7 @@ struct CaretValueFormat3
   inline int get_caret_value (hb_ot_layout_context_t *c, hb_codepoint_t glyph_id HB_UNUSED) const
   {
     /* TODO vertical */
-    return c->scale_x (coordinate) +
-	   ((this+deviceTable).get_delta (c->font->x_ppem) * c->font->x_scale);
+    return c->scale_x (coordinate) + ((this+deviceTable).get_x_delta (c));
   }
 
   inline bool sanitize (hb_sanitize_context_t *c) {
diff --git a/src/hb-ot-layout-gpos-private.hh b/src/hb-ot-layout-gpos-private.hh
index 10e9df578..77cbbeba2 100644
--- a/src/hb-ot-layout-gpos-private.hh
+++ b/src/hb-ot-layout-gpos-private.hh
@@ -112,16 +112,16 @@ struct ValueFormat : USHORT
 
     /* pixel -> fractional pixel */
     if (format & xPlaDevice) {
-      if (x_ppem) glyph_pos.x_offset  += (base + get_device (values++)).get_delta (x_ppem) * layout->font->x_scale; else values++;
+      if (x_ppem) glyph_pos.x_offset  += (base + get_device (values++)).get_x_delta (layout); else values++;
     }
     if (format & yPlaDevice) {
-      if (y_ppem) glyph_pos.y_offset  += (base + get_device (values++)).get_delta (y_ppem) * layout->font->y_scale; else values++;
+      if (y_ppem) glyph_pos.y_offset  += (base + get_device (values++)).get_y_delta (layout); else values++;
     }
     if (format & xAdvDevice) {
-      if (x_ppem) glyph_pos.x_advance += (base + get_device (values++)).get_delta (x_ppem) * layout->font->x_scale; else values++;
+      if (x_ppem) glyph_pos.x_advance += (base + get_device (values++)).get_x_delta (layout); else values++;
     }
     if (format & yAdvDevice) {
-      if (y_ppem) glyph_pos.y_advance += (base + get_device (values++)).get_delta (y_ppem) * layout->font->y_scale; else values++;
+      if (y_ppem) glyph_pos.y_advance += (base + get_device (values++)).get_y_delta (layout); else values++;
     }
   }
 
@@ -268,9 +268,9 @@ struct AnchorFormat3
 
       /* pixel -> fractional pixel */
       if (layout->font->x_ppem)
-	*x += (this+xDeviceTable).get_delta (layout->font->x_ppem) * layout->font->x_scale;
+	*x += (this+xDeviceTable).get_x_delta (layout);
       if (layout->font->y_ppem)
-	*y += (this+yDeviceTable).get_delta (layout->font->y_ppem) * layout->font->y_scale;
+	*y += (this+yDeviceTable).get_x_delta (layout);
   }
 
   inline bool sanitize (hb_sanitize_context_t *c) {
diff --git a/src/hb-ot-layout-private.hh b/src/hb-ot-layout-private.hh
index 723db4457..71d725382 100644
--- a/src/hb-ot-layout-private.hh
+++ b/src/hb-ot-layout-private.hh
@@ -76,7 +76,7 @@ struct hb_ot_layout_context_t
   } info;
 
   /* Convert from font-space to user-space */
-  /* XXX div-by-zero */
+  /* XXX div-by-zero / speed up */
   inline hb_position_t scale_x (int16_t v) { return (int64_t) this->font->x_scale * v / this->face->head_table->unitsPerEm; }
   inline hb_position_t scale_y (int16_t v) { return (int64_t) this->font->y_scale * v / this->face->head_table->unitsPerEm; }
 };