Atom/rbarrand/export screenshot diff (#7300)

* Small refactor on ImageComparison utils.

Signed-off-by: hershey5045 <43485729+hershey5045@users.noreply.github.com>

* Add aznumeric cast.

Signed-off-by: hershey5045 <43485729+hershey5045@users.noreply.github.com>

* Correction on aznumeric cast.

Signed-off-by: hershey5045 <43485729+hershey5045@users.noreply.github.com>

* Add unit test for new image comparison function.

Signed-off-by: hershey5045 <43485729+hershey5045@users.noreply.github.com>

* Use span instead of array_view

Signed-off-by: hershey5045 <43485729+hershey5045@users.noreply.github.com>

Gems/Atom/Utils/Code/Include/Atom/Utils/ImageComparison.h

@@ -24,7 +24,7 @@ namespace AZ
         };
 
         //! Calculates the maximum difference of the rgb channels between two image buffers.
-        int16_t CalcMaxChannelDifference(AZStd::array_view<uint8_t> bufferA, AZStd::array_view<uint8_t> bufferB, size_t index);
+        int16_t CalcMaxChannelDifference(AZStd::span<const uint8_t> bufferA, AZStd::span<const uint8_t> bufferB, size_t index);
 
         //! Compares two images and returns the RMS (root mean square) of the difference.
         //! @param buffer[A|B] the raw buffer of image data

Gems/Atom/Utils/Code/Source/ImageComparison.cpp

@@ -14,7 +14,7 @@ namespace AZ
 {
     namespace Utils
     {
-        int16_t CalcMaxChannelDifference(AZStd::array_view<uint8_t> bufferA, AZStd::array_view<uint8_t> bufferB, size_t index)
+        int16_t CalcMaxChannelDifference(AZStd::span<const uint8_t> bufferA, AZStd::span<const uint8_t> bufferB, size_t index)
         {
             // We use the max error from a single channel instead of accumulating the error from each channel.
             // This normalizes differences so that for example black vs red has the same weight as black vs yellow.