Add flexible keybinding/command system to sk_app

tools/viewer/sk_app/CommandSet.h

Index: tools/viewer/sk_app/CommandSet.h
diff --git a/tools/viewer/sk_app/CommandSet.h b/tools/viewer/sk_app/CommandSet.h
new file mode 100644
index 0000000000000000000000000000000000000000..39481079376a0a65531e1b3ecc8f91a8935745d8
--- /dev/null
+++ b/tools/viewer/sk_app/CommandSet.h
@@ -0,0 +1,91 @@
+/*
+* Copyright 2016 Google Inc.
+*
+* Use of this source code is governed by a BSD-style license that can be
+* found in the LICENSE file.
+*/
+
+#ifndef CommandSet_DEFINED
+#define CommandSet_DEFINED
+
+#include "SkString.h"
+#include "Window.h"
+
+#include <functional>
+
+class SkCanvas;
+
+namespace sk_app {
+
+class CommandSet {

[bsalomon, 2016/05/09 20:25:53]

Maybe a little bit of comment text to explain what this is for?

+public:
+    CommandSet();
+
+    void attach(Window* window);
+    bool onKey(sk_app::Window::Key key, sk_app::Window::InputState state, uint32_t modifiers);
+    bool onChar(SkUnichar, uint32_t modifiers);
+
+    void addCommand(SkUnichar c, const char* group, const char* description,
+                    std::function<void(void)> function);
+    void addCommand(Window::Key k, const char* keyName, const char* group, const char* description,
+                    std::function<void(void)> function);
+
+    void drawHelp(SkCanvas* canvas);
+
+private:
+    struct Command {
+        enum CommandType {
+            kChar_CommandType,
+            kKey_CommandType,
+        };
+
+        Command(SkUnichar c, const char* group, const char* description,
+                std::function<void(void)> function)
+            : fType(kChar_CommandType)
+            , fChar(c)
+            , fKeyName(SkStringPrintf("%c", c))
+            , fGroup(group)
+            , fDescription(description)
+            , fFunction(function) {}
+
+        Command(Window::Key k, const char* keyName, const char* group, const char* description,
+                std::function<void(void)> function)
+            : fType(kKey_CommandType)
+            , fKey(k)
+            , fKeyName(keyName)
+            , fGroup(group)
+            , fDescription(description)
+            , fFunction(function) {}
+
+        CommandType fType;
+
+        // For kChar_CommandType
+        SkUnichar fChar;
+
+        // For kKey_CommandType
+        Window::Key fKey;
+
+        // Common to all command types
+        SkString fKeyName;
+        SkString fGroup;
+        SkString fDescription;
+        std::function<void(void)> fFunction;
+    };
+
+    static bool compareCommandKey(const Command& first, const Command& second);
+    static bool compareCommandGroup(const Command& first, const Command& second);
+
+    enum HelpMode {
+        kNone_HelpMode,
+        kGrouped_HelpMode,
+        kAlphabetical_HelpMode,
+    };
+
+    Window*           fWindow;
+    SkTArray<Command> fCommands;
+    HelpMode          fHelpMode;
+};
+
+}   // namespace sk_app
+
+#endif