TextureTools: take a strided view in atlasArrayPowerOfTwo().

Together with the parent commit, it's now possible to do THE
UNTHINKABLE:

    Containers::Array<Trade::ImageData2D> inputImages = ...;

    auto out = TextureTools::atlasArrayPowerOfTwo({2048, 2048},
        stridedArrayView(inputImages).slice(&Trade::ImageData2D::size));

An actual use case, in fact. Because why not.

src/Magnum/TextureTools/Atlas.cpp

@@ -28,6 +28,7 @@
 #include <algorithm>
 #include <vector>
 #include <Corrade/Containers/Array.h>
+#include <Corrade/Containers/StridedArrayView.h>
 #include <Corrade/Containers/Pair.h>
 
 #include "Magnum/Math/Functions.h"
@@ -64,7 +65,7 @@ std::vector<Range2Di> atlas(const Vector2i& atlasSize, const std::vector<Vector2
     return atlas;
 }
 
-Containers::Pair<Int, Containers::Array<Vector3i>> atlasArrayPowerOfTwo(const Vector2i& layerSize, const Containers::ArrayView<const Vector2i> sizes) {
+Containers::Pair<Int, Containers::Array<Vector3i>> atlasArrayPowerOfTwo(const Vector2i& layerSize, const Containers::StridedArrayView1D<const Vector2i> sizes) {
     CORRADE_ASSERT(layerSize.product() && layerSize.x() == layerSize.y() && (layerSize & (layerSize - Vector2i{1})).isZero(),
         "TextureTools::atlasArrayPowerOfTwo(): expected layer size to be a non-zero power-of-two square, got" << Debug::packed << layerSize, {});
 
@@ -140,7 +141,7 @@ Containers::Pair<Int, Containers::Array<Vector3i>> atlasArrayPowerOfTwo(const Ve
 }
 
 Containers::Pair<Int, Containers::Array<Vector3i>> atlasArrayPowerOfTwo(const Vector2i& layerSize, const std::initializer_list<Vector2i> sizes) {
-    return atlasArrayPowerOfTwo(layerSize, Containers::arrayView(sizes));
+    return atlasArrayPowerOfTwo(layerSize, Containers::stridedArrayView(sizes));
 }
 
 }}

src/Magnum/TextureTools/Atlas.h

@@ -72,7 +72,7 @@ atlasing in a single @f$ \mathcal{O}(n) @f$ operation. Due to the sort
 involved, a temporary allocation holds the sorted array and additionally
 @ref std::stable_sort() performs its own allocation.
 */
-Containers::Pair<Int, Containers::Array<Vector3i>> MAGNUM_TEXTURETOOLS_EXPORT atlasArrayPowerOfTwo(const Vector2i& layerSize, Containers::ArrayView<const Vector2i> sizes);
+Containers::Pair<Int, Containers::Array<Vector3i>> MAGNUM_TEXTURETOOLS_EXPORT atlasArrayPowerOfTwo(const Vector2i& layerSize, Containers::StridedArrayView1D<const Vector2i> sizes);
 
 /**
  * @overload

src/Magnum/TextureTools/Test/AtlasTest.cpp

@@ -27,6 +27,7 @@
 #include <vector>
 #include <Corrade/Containers/Array.h>
 #include <Corrade/Containers/Pair.h>
+#include <Corrade/Containers/StridedArrayView.h>
 #include <Corrade/TestSuite/Tester.h>
 #include <Corrade/TestSuite/Compare/Container.h>
 #include <Corrade/Utility/DebugStl.h>