Fixing SkTileGrid to clamp rather than clip content and querries that are outside the bounds of the…

include/core/SkMath.h

Index: include/core/SkMath.h
===================================================================
--- include/core/SkMath.h	(revision 8533)
+++ include/core/SkMath.h	(working copy)
@@ -55,6 +55,17 @@
     return value & ~(value >> 31);
 }
 
+/** Given an integer and an integer range, return the value
+ *  pinned against min and max, inclusive.
+ *  @param value    The value we want returned pinned between [min...max]

[Tom Hudson, 2013/04/09 10:10:50]

Nit: Skia doesn't usually use @param when it's completely redundant, as here.

+ *  @param min      The min value
+ *  @param max      The max value
+ *  @return min if value < min, max if value > max, else value
+ */
+static inline int SkClampMinMax(int value, int min, int max) {

[Tom Hudson, 2013/04/09 10:10:50]

Given that SkClampMax doesn't use the trinary operator, you could follow this up
by checking generated assembly, or just comparing performance? Maybe it doesn't
make a difference...

[Justin Novosad, 2013/04/09 14:47:50]

Ternary operators are actually more likely to trigger optimizations (e.g. the MS
compiler avoids branching by using conditional assignment x86 instruction) 

Anyways, I agree. This should be micro-benched and tuned. skbug.com/1215

+    return (value < min ? min : (value > max ? max : value));
+}
+
 /** Given an integer and a positive (max) integer, return the value
  *  pinned against 0 and max, inclusive.
  *  @param value    The value we want returned pinned between [0...max]