Remove SampleApp and convert HelloWorld to sk_app

There is still a large amount of views code that could be trimmed down,
but which is used to implement samples (in viewer). Seemed simpler to
remove some of this code in pieces.

Bug: skia:
Change-Id: Ia3415060d03c8de604a154e3dc38379b754daab6
Reviewed-on: https://skia-review.googlesource.com/72801
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>

1 files changed, 117 insertions, 0 deletions

diff --git a/tools/sk_app/CommandSet.h b/tools/sk_app/CommandSet.h
new file mode 100644
index 0000000000..0784a3875e
--- /dev/null
+++ b/tools/sk_app/CommandSet.h
@@ -0,0 +1,117 @@
+/*
+* 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>
+#include <vector>
+
+class SkCanvas;
+
+namespace sk_app {
+
+/**
+ * Helper class used by applications that want to hook keypresses to trigger events.
+ *
+ * An app can simply store an instance of CommandSet and then use it as follows:
+ * 1) Attach to the Window at initialization time.
+ * 2) Register commands to be executed for characters or keys. Each command needs a Group and a
+ *    description (both just strings). Commands attached to Keys (rather than characters) also need
+ *    a displayable name for the Key. Finally, a function to execute when the key or character is
+ *    pressed must be supplied. The easiest option to is pass in a lambda that captures [this]
+ *    (your application object), and performs whatever action is desired.
+ * 3) Register key and char handlers with the Window, and - depending on your state - forward those
+ *    events to the CommandSet's onKey, onChar, and onSoftKey.
+ * 4) At the end of your onPaint, call drawHelp, and pass in the application's canvas.
+
+ * The CommandSet always binds 'h' to cycle through two different help screens. The first shows
+ * all commands, organized by Group (with headings for each Group). The second shows all commands
+ * alphabetically by key/character.
+ */
+class CommandSet {
+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);
+    bool onSoftkey(const SkString& softkey);
+
+    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);
+
+    std::vector<SkString> getCommandsAsSoftkeys() const;
+
+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(' ' == c ? SkString("Space") : 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;
+
+        SkString getSoftkeyString() const {
+            return SkStringPrintf("%s (%s)", fKeyName.c_str(), fDescription.c_str());
+        }
+    };
+
+    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