ImGuiIntegration: Add conversion between ImStrv and StringView

src/Magnum/ImGuiIntegration/Integration.h

@@ -57,11 +57,27 @@ Example usage:
 #include "Magnum/ImGuiIntegration/visibility.h" /* defines IMGUI_API */
 
 #include <imgui.h>
+#include <Corrade/Containers/StringView.h>
 #include <Magnum/Types.h>
 #include <Magnum/Math/Vector.h>
 
-/* Don't list (useless) Magnum and Math namespaces without anything else */
+/* Don't list (useless) Corrade and Magnum and Math namespaces without anything else */
 #ifndef DOXYGEN_GENERATING_OUTPUT
+
+/* Currently present only in the features/string_view branch of ImGui */
+#ifdef IMGUI_HAS_IMSTR
+namespace Corrade { namespace Containers { namespace Implementation {
+
+template<> struct StringViewConverter<const char, ImStrv> {
+    static StringView from(const ImStrv& other) {
+        return StringView{other.Begin, other.length()};
+    }
+    static ImStrv to(StringView other) { return ImStrv{other.begin(), other.end()}; }
+};
+
+}}}
+#endif
+
 namespace Magnum { namespace Math { namespace Implementation {
 
 /* ImVec2 */

src/Magnum/ImGuiIntegration/Test/IntegrationTest.cpp

@@ -35,19 +35,33 @@ namespace Magnum { namespace ImGuiIntegration { namespace Test { namespace {
 struct IntegrationTest: TestSuite::Tester {
     explicit IntegrationTest();
 
+    void stringView();
     void vector2();
     void vector4();
     void color();
     void colorLiterals();
 };
 
 IntegrationTest::IntegrationTest() {
-    addTests({&IntegrationTest::vector2,
+    addTests({&IntegrationTest::stringView,
+              &IntegrationTest::vector2,
               &IntegrationTest::vector4,
               &IntegrationTest::color,
               &IntegrationTest::colorLiterals});
 }
 
+void IntegrationTest::stringView() {
+#ifdef IMGUI_HAS_IMSTR
+    ImStrv imStrv{"Hello World!"};
+    StringView stringView("Hello World!");
+
+    CORRADE_COMPARE(StringView(imVec2), vec2);
+
+    ImStrv c(stringView);
+    CORRADE_COMPARE(c, stringView);
+#endif
+}
+
 void IntegrationTest::vector2() {
     ImVec2 imVec2{1.1f, 1.2f};
     Vector2 vec2(1.1f, 1.2f);