Throws exception for colored images that don't have 8 bits per color

Summary:
@public

Throws an exception for RGB/CMYK images whose colors are represented with something else that 8 bits. This is the case for kCGImagePixelFormatRGB555.

Reviewed By: cuva

Differential Revision: D15625249

fbshipit-source-id: a0ee5199e4d55220d1631e994a52c51cfe3c0a76

ios/SpectrumKit/SpectrumKit/Image/FSPImagePixelSpecification.mm

@@ -235,10 +235,16 @@ + (instancetype)imagePixelSpecificationColorModelFromImage:(UIImage *)image
       return FSPImagePixelSpecificationColorModel.unknown;
     case kCGColorSpaceModelMonochrome:
       return FSPImagePixelSpecificationColorModel.gray;
-    case kCGColorSpaceModelRGB:
+    case kCGColorSpaceModelRGB: {
+      const auto bitsPerComponent = CGImageGetBitsPerComponent(image.CGImage);
+      SPECTRUM_ERROR_FORMAT_IF(bitsPerComponent != 8, "unsupported_image_pixel_spec_rgb_bits_per_component", "%d", bitsPerComponent);
       return FSPImagePixelSpecificationColorModel.rgb;
-    case kCGColorSpaceModelCMYK:
+    }
+    case kCGColorSpaceModelCMYK: {
+      const auto bitsPerComponent = CGImageGetBitsPerComponent(image.CGImage);
+      SPECTRUM_ERROR_FORMAT_IF(bitsPerComponent != 8, "unsupported_image_pixel_spec_cmyk_bits_per_component", "%d", bitsPerComponent);
       return FSPImagePixelSpecificationColorModel.yCbCr;
+    }
     case kCGColorSpaceModelLab:
     case kCGColorSpaceModelDeviceN:
     case kCGColorSpaceModelIndexed: