ios fixes

skia_ios.mm
Get the app's Documents directory and pass use it to set the resource path.
This is a quick hack which will be replaced by a new application that is
a tiny shim around a command line tool.

SkImageEncoder.h
SkForceLinking.cpp
SkImageDecoder_CG.cpp
Add support for FORCE_LINKING so iOS sees the PNG encoder and others.

SkFloatBits.cpp
SkPoint.cpp
Handle denormalized numbers that are floored by the iOS ARM processor.

SkImageDecoder_iOS.mm
Remove empty encoder factory.

SkTouchGesture.cpp
Return early on empty state on touch rather than aborting (crashing)

JpegTest.cpp
Hal via stackoverflow.com says partial jpegs can be gray as well.

skia_test.cpp
Remove crash handler call for now to avoid link failure.

OverwriteLine.h
Remove fancy line overwrite for iOS.

Resources.cpp
Add interface to set resource directory based on runtime query.

BUG=skia:2736 skia:2737 skia:2738
R=reed@google.com, halcanary@google.com, mtklein@google.com, tfarina@chromium.org

Author: caryclark@google.com

Review URL: https://codereview.chromium.org/373383003

7 files changed, 53 insertions, 4 deletions

diff --git a/src/core/SkFloatBits.cpp b/src/core/SkFloatBits.cpp
index 39b51abf1d..6b35a75c88 100644
--- a/src/core/SkFloatBits.cpp
+++ b/src/core/SkFloatBits.cpp
@@ -85,7 +85,16 @@ int32_t SkFloatBits_toIntFloor(int32_t packed) {
         value = SkApplySign(value, SkExtractSign(packed));
         exp = -exp;
         if (exp > 25) {   // underflow
+#ifdef SK_DISCARD_DENORMALIZED_FOR_SPEED
+        // The iOS ARM processor discards small denormalized numbers to go faster.
+        // The comparision below empirically causes the result to agree with the
+        // tests in MathTest test_float_floor
+            if (exp > 149) {
+                return 0;
+            }
+#else
             exp = 25;
+#endif
         }
         // int add = 0;
         return value >> exp;
@@ -145,7 +154,17 @@ int32_t SkFloatBits_toIntCeil(int32_t packed) {
         value = SkApplySign(value, SkExtractSign(packed));
         exp = -exp;
         if (exp > 25) {   // underflow
+#ifdef SK_DISCARD_DENORMALIZED_FOR_SPEED
+        // The iOS ARM processor discards small denormalized numbers to go faster.
+        // The comparision below empirically causes the result to agree with the
+        // tests in MathTest test_float_ceil
+            if (exp > 149) {
+                return 0;
+            }
+            return 0 < value;
+#else
             exp = 25;
+#endif
         }
         int add = (1 << exp) - 1;
         return (value + add) >> exp;
diff --git a/src/core/SkMathPriv.h b/src/core/SkMathPriv.h
index f93ab61078..e997045ea8 100644
--- a/src/core/SkMathPriv.h
+++ b/src/core/SkMathPriv.h
@@ -10,6 +10,12 @@
 
 #include "SkMath.h"
 
+#ifdef SK_BUILD_FOR_IOS
+// The iOS ARM processor discards small denormalized numbers to go faster.
+// Algorithms that rely on denormalized numbers need alternative implementations.
+#define SK_DISCARD_DENORMALIZED_FOR_SPEED
+#endif
+
 /** Returns -1 if n < 0, else returns 0
  */
 #define SkExtractSign(n)    ((int32_t)(n) >> 31)
diff --git a/src/core/SkPoint.cpp b/src/core/SkPoint.cpp
index 719ee54b22..8a6d0564af 100644
--- a/src/core/SkPoint.cpp
+++ b/src/core/SkPoint.cpp
@@ -7,6 +7,7 @@
  */
 
 
+#include "SkMathPriv.h"
 #include "SkPoint.h"
 
 void SkIPoint::rotateCW(SkIPoint* dst) const {
@@ -168,7 +169,17 @@ bool SkPoint::setLength(float x, float y, float length) {
         // divide by inf. and return (0,0) vector.
         double xx = x;
         double yy = y;
+    #ifdef SK_DISCARD_DENORMALIZED_FOR_SPEED
+        // The iOS ARM processor discards small denormalized numbers to go faster.
+        // Casting this to a float would cause the scale to go to zero. Keeping it
+        // as a double for the multiply keeps the scale non-zero.
+        double dscale = length / sqrt(xx * xx + yy * yy);
+        fX = x * dscale;
+        fY = y * dscale;
+        return true;
+    #else
         scale = (float)(length / sqrt(xx * xx + yy * yy));
+    #endif
     }
     fX = x * scale;
     fY = y * scale;
diff --git a/src/images/SkForceLinking.cpp b/src/images/SkForceLinking.cpp
index 2c9a38979a..442f0f77c0 100644
--- a/src/images/SkForceLinking.cpp
+++ b/src/images/SkForceLinking.cpp
@@ -29,6 +29,9 @@ int SkForceLinking(bool doNotPassTrue) {
 #if !defined(SK_BUILD_FOR_MAC) && !defined(SK_BUILD_FOR_WIN) && !defined(SK_BUILD_FOR_IOS)
         CreatePNGImageDecoder();
 #endif
+#if defined(SK_BUILD_FOR_IOS)
+        CreatePNGImageEncoder_IOS();
+#endif
         return -1;
     }
     return 0;
diff --git a/src/ports/SkImageDecoder_CG.cpp b/src/ports/SkImageDecoder_CG.cpp
index 7bebf394da..5b32502d8e 100644
--- a/src/ports/SkImageDecoder_CG.cpp
+++ b/src/ports/SkImageDecoder_CG.cpp
@@ -300,6 +300,17 @@ static SkImageEncoder* sk_imageencoder_cg_factory(SkImageEncoder::Type t) {
 
 static SkImageEncoder_EncodeReg gEReg(sk_imageencoder_cg_factory);
 
+#ifdef SK_BUILD_FOR_IOS
+class SkPNGImageEncoder_IOS : public SkImageEncoder_CG {
+public:
+    SkPNGImageEncoder_IOS()
+        : SkImageEncoder_CG(kPNG_Type) {
+    }
+};
+
+DEFINE_ENCODER_CREATOR(PNGImageEncoder_IOS);
+#endif
+
 struct FormatConversion {
     CFStringRef             fUTType;
     SkImageDecoder::Format  fFormat;
diff --git a/src/utils/ios/SkImageDecoder_iOS.mm b/src/utils/ios/SkImageDecoder_iOS.mm
index 021fa25309..f3db65e035 100755
--- a/src/utils/ios/SkImageDecoder_iOS.mm
+++ b/src/utils/ios/SkImageDecoder_iOS.mm
@@ -62,7 +62,4 @@ SkMovie* SkMovie::DecodeStream(SkStreamRewindable* stream) {
     return NULL;
 }
 
-SkImageEncoder* SkImageEncoder::Create(Type t) {
-    return NULL;
-}
 
diff --git a/src/views/SkTouchGesture.cpp b/src/views/SkTouchGesture.cpp
index 9b02417771..e6a8eaeec6 100644
--- a/src/views/SkTouchGesture.cpp
+++ b/src/views/SkTouchGesture.cpp
@@ -203,7 +203,9 @@ float SkTouchGesture::limitTotalZoom(float scale) const {
 void SkTouchGesture::touchMoved(void* owner, float x, float y) {
 //    GrPrintf("--- %d touchMoved %p %g %g\n", fTouches.count(), owner, x, y);
 
-    SkASSERT(kEmpty_State != fState);
+    if (kEmpty_State == fState) {
+        return;
+    }
 
     int index = this->findRec(owner);
     if (index < 0) {