Check defines to build for mac or ios

This starts a pattern in rive_types.hpp where we do some common compiler-define checking, to determine which platform we compiling on. The specific goal here is to allow cg_skia_factory.cpp to build on both OSX and iOS (just needs different includes)

Diffs=
b515308af Check defines to build for mac or ios

.rive_head

diff --git a/.rive_head b/.rive_head
index 24f2dd3..0be0140 100644
--- a/.rive_head
+++ b/.rive_head
@@ -1 +1 @@
-99b96518a27fd47f231ba4bb17148ac2099e14d1
+b515308af7839e87f7b5fee7859a703d820a7026

include/rive/rive_types.hpp

diff --git a/include/rive/rive_types.hpp b/include/rive/rive_types.hpp
index 3723aea..2bdf100 100644
--- a/include/rive/rive_types.hpp
+++ b/include/rive/rive_types.hpp
@@ -32,6 +32,21 @@
 #endif
 #endif
 
+// Some checks to guess what platform we're building for
+
+#ifdef __APPLE__
+
+    #define RIVE_BUILD_FOR_APPLE
+    #include <TargetConditionals.h>
+
+    #if TARGET_OS_IPHONE
+        #define RIVE_BUILD_FOR_IOS
+    #elif TARGET_OS_MAC
+        #define RIVE_BUILD_FOR_OSX
+    #endif
+
+#endif
+
 // We really like these headers, so we include them all the time.
 
 #include <algorithm>

skia/viewer/src/cg_skia_factory.cpp

diff --git a/skia/viewer/src/cg_skia_factory.cpp b/skia/viewer/src/cg_skia_factory.cpp
index 0e6baee..7ffad4d 100644
--- a/skia/viewer/src/cg_skia_factory.cpp
+++ b/skia/viewer/src/cg_skia_factory.cpp
@@ -3,11 +3,18 @@
  */
 
 #include "cg_skia_factory.hpp"
-
-#include <ApplicationServices/ApplicationServices.h>
-
+#include "rive/core/type_conversions.hpp"
 #include <vector>
 
+#ifdef RIVE_BUILD_FOR_APPLE
+
+#if defined(RIVE_BUILD_FOR_OSX)
+    #include <ApplicationServices/ApplicationServices.h>
+#elif defined(RIVE_BUILD_FOR_IOS)
+    #include <CoreGraphics/CoreGraphics.h>
+    #include <ImageIO/ImageIO.h>
+#endif
+
 // Helper that remembers to call CFRelease when an object goes out of scope.
 template <typename T> class AutoCF {
     T m_Obj;
@@ -22,7 +29,8 @@
 
 using namespace rive;
 
-std::vector<uint8_t> CGSkiaFactory::platformDecode(rive::Span<const uint8_t> span, ImageInfo* info) {
+std::vector<uint8_t> CGSkiaFactory::platformDecode(Span<const uint8_t> span,
+                                                   SkiaFactory::ImageInfo* info) {
     std::vector<uint8_t> pixels;
 
     AutoCF data = CFDataCreateWithBytesNoCopy(nullptr, span.data(), span.size(), nullptr);
@@ -60,8 +68,8 @@
     } else {
         cgInfo |= kCGImageAlphaPremultipliedLast; // premul
     }
-    const int width = CGImageGetWidth(image);
-    const int height = CGImageGetHeight(image);
+    const size_t width = CGImageGetWidth(image);
+    const size_t height = CGImageGetHeight(image);
     const size_t rowBytes = width * 4;  // 4 bytes per pixel
     const size_t size = rowBytes * height;
 
@@ -79,8 +87,10 @@
 
     info->alphaType = isOpaque ? AlphaType::opaque : AlphaType::premul;
     info->colorType = ColorType::rgba;
-    info->width = width;
-    info->height = height;
+    info->width = castTo<uint32_t>(width);
+    info->height = castTo<uint32_t>(height);
     info->rowBytes = rowBytes;
     return pixels;
 };
+
+#endif  // RIVE_BUILD_FOR_APPLE

skia/viewer/src/cg_skia_factory.hpp

diff --git a/skia/viewer/src/cg_skia_factory.hpp b/skia/viewer/src/cg_skia_factory.hpp
index 77557eb..050735f 100644
--- a/skia/viewer/src/cg_skia_factory.hpp
+++ b/skia/viewer/src/cg_skia_factory.hpp
@@ -8,11 +8,10 @@
 #include "skia_factory.hpp"
 
 namespace rive {
-
 struct CGSkiaFactory : public SkiaFactory {
-    std::vector<uint8_t> platformDecode(rive::Span<const uint8_t> span, ImageInfo* info) override;
+    std::vector<uint8_t> platformDecode(Span<const uint8_t>,
+                                        SkiaFactory::ImageInfo*) override;
 };
-
 } // namespace
 
-#endif
+#endif // _RIVE_CGSkiaFactory_HPP_