Deprecate templated [Compressed]Image{,View,Data}::data().

This one returned a raw pointer, losing all size information, One should
instead use the non-templated data() along with Containers::arrayCast()
for a properly type-checked conversion.

There's *a lot* of tests using the deprecated functionality. I need to
change one more thing before updating those.

doc/changelog.dox

@@ -489,6 +489,12 @@ See also:
     is deprecated for doing too many things at once and being too tied to one
     particular STL container, use @ref MeshTools::generateFlatNormals(const Containers::StridedArrayView1D<const Vector3>&)
     instead
+-   Templated versions of @ref Image::data(), @ref ImageView::data(),
+    @ref CompressedImage::data(), @ref CompressedImageView::data() and
+    @ref Trade::ImageData::data() that returned a raw pointer are deprecated,
+    use the non-templated version together with
+    @ref Corrade::Containers::arrayCast() instead for properly bounds-checked
+    type conversion
 
 @subsection changelog-latest-compatibility Potential compatibility breakages, removed APIs
 

src/Magnum/Image.h

@@ -364,15 +364,27 @@ template<UnsignedInt dimensions> class Image {
         Containers::ArrayView<const char> data() const & { return _data; }
         Containers::ArrayView<const char> data() const && = delete; /**< @overload */
 
-        /** @overload */
-        template<class T = char> T* data() {
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") T* data() {
             return reinterpret_cast<T*>(_data.data());
         }
 
-        /** @overload */
-        template<class T = char> const T* data() const {
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") const T* data() const {
             return reinterpret_cast<const T*>(_data.data());
         }
+        #endif
 
         /**
          * @brief View on pixel data
@@ -580,15 +592,27 @@ template<UnsignedInt dimensions> class CompressedImage {
         /** @overload */
         Containers::ArrayView<const char> data() const { return _data; }
 
-        /** @overload */
-        template<class T> T* data() {
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") T* data() {
             return reinterpret_cast<T*>(_data.data());
         }
 
-        /** @overload */
-        template<class T> const T* data() const {
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") const T* data() const {
             return reinterpret_cast<const T*>(_data.data());
         }
+        #endif
 
         /**
          * @brief Release data storage

src/Magnum/ImageView.h

@@ -373,10 +373,17 @@ template<UnsignedInt dimensions> class ImageView {
          */
         Containers::ArrayView<const char> data() const { return _data; }
 
-        /** @overload */
-        template<class T> const T* data() const {
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") const T* data() const {
             return reinterpret_cast<const T*>(_data.data());
         }
+        #endif
 
         /**
          * @brief Set image data
@@ -612,10 +619,17 @@ template<UnsignedInt dimensions> class CompressedImageView {
         /** @brief Image data */
         Containers::ArrayView<const char> data() const { return _data; }
 
-        /** @overload */
-        template<class T> const T* data() const {
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") const T* data() const {
             return reinterpret_cast<const T*>(_data.data());
         }
+        #endif
 
         /**
          * @brief Set image data

src/Magnum/Trade/ImageData.h

@@ -340,15 +340,27 @@ template<UnsignedInt dimensions> class ImageData {
         Containers::ArrayView<const char> data() const & { return _data; }
         Containers::ArrayView<const char> data() const && = delete; /**< @overload */
 
-        /** @overload */
-        template<class T> T* data() {
+        #ifdef MAGNUM_BUILD_DEPRECATED
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") T* data() {
             return reinterpret_cast<T*>(_data.data());
         }
 
-        /** @overload */
-        template<class T> const T* data() const {
+        /**
+         * @brief Image data in a particular type
+         * @deprecated Use non-templated @ref data() together with
+         *      @ref Corrade::Containers::arrayCast() instead for properly
+         *      bounds-checked type conversion.
+         */
+        template<class T> CORRADE_DEPRECATED("use data() together with Containers::arrayCast() instead") const T* data() const {
             return reinterpret_cast<const T*>(_data.data());
         }
+        #endif
 
         /**
          * @brief View on pixel data