Add flexible keybinding/command system to sk_app

tools/viewer/sk_app/CommandSet.cpp

Index: tools/viewer/sk_app/CommandSet.cpp
diff --git a/tools/viewer/sk_app/CommandSet.cpp b/tools/viewer/sk_app/CommandSet.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e426eaab210dca55e838c2368352bb305bcb36f2
--- /dev/null
+++ b/tools/viewer/sk_app/CommandSet.cpp
@@ -0,0 +1,157 @@
+/*
+* Copyright 2016 Google Inc.
+*
+* Use of this source code is governed by a BSD-style license that can be
+* found in the LICENSE file.
+*/
+
+#include "CommandSet.h"
+
+#include "SkCanvas.h"
+#include "SkTSort.h"
+
+namespace sk_app {
+
+static bool on_key_handler(Window::Key key, Window::InputState state, uint32_t modifiers,
+                           void* userData) {
+    CommandSet* cs = reinterpret_cast<CommandSet*>(userData);
+    return cs->onKey(key, state, modifiers);
+}
+
+static bool on_char_handler(SkUnichar c, uint32_t modifiers, void* userData) {
+    CommandSet* cs = reinterpret_cast<CommandSet*>(userData);
+    return cs->onChar(c, modifiers);
+}
+
+CommandSet::CommandSet()
+    : fHelpMode(kNone_HelpMode) {
+    this->addCommand('h', "Overlays", "Show help screen", [this]() {
+        switch (this->fHelpMode) {
+            case kNone_HelpMode:
+                this->fHelpMode = kGrouped_HelpMode;
+                break;
+            case kGrouped_HelpMode:
+                this->fHelpMode = kAlphabetical_HelpMode;
+                break;
+            case kAlphabetical_HelpMode:
+                this->fHelpMode = kNone_HelpMode;
+                break;
+        }
+        fWindow->inval();
+    });
+}
+
+void CommandSet::attach(Window* window) {
+    fWindow = window;
+    window->registerKeyFunc(on_key_handler, this);
+    window->registerCharFunc(on_char_handler, this);
+}
+
+bool CommandSet::onKey(Window::Key key, Window::InputState state, uint32_t modifiers) {
+    if (Window::kDown_InputState == state) {
+        for (Command& cmd : fCommands) {
+            if (Command::kKey_CommandType == cmd.fType && key == cmd.fKey) {
+                cmd.fFunction();
+                return true;
+            }
+        }
+    }
+
+    return false;
+}
+
+bool CommandSet::onChar(SkUnichar c, uint32_t modifiers) {
+    for (Command& cmd : fCommands) {
+        if (Command::kChar_CommandType == cmd.fType && c == cmd.fChar) {
+            cmd.fFunction();
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void CommandSet::addCommand(SkUnichar c, const char* group, const char* description,
+                            std::function<void(void)> function) {
+    fCommands.push_back(Command(c, group, description, function));
+}
+
+void CommandSet::addCommand(Window::Key k, const char* keyName, const char* group,
+                            const char* description, std::function<void(void)> function) {
+    fCommands.push_back(Command(k, keyName, group, description, function));
+}
+
+#if defined(SK_BUILD_FOR_WIN32)
+    #define SK_strcasecmp   _stricmp
+#else
+    #define SK_strcasecmp   strcasecmp
+#endif
+
+bool CommandSet::compareCommandKey(const Command& first, const Command& second) {
+    return SK_strcasecmp(first.fKeyName.c_str(), second.fKeyName.c_str()) < 0;
+}
+
+bool CommandSet::compareCommandGroup(const Command& first, const Command& second) {
+    return SK_strcasecmp(first.fGroup.c_str(), second.fGroup.c_str()) < 0;
+}
+
+void CommandSet::drawHelp(SkCanvas* canvas) {
+    if (kNone_HelpMode == fHelpMode) {
+        return;
+    }
+
+    // Sort commands for current mode:
+    SkTQSort(fCommands.begin(), fCommands.end() - 1,
+             kAlphabetical_HelpMode == fHelpMode ? compareCommandKey : compareCommandGroup);
+
+    SkPaint bgPaint;
+    bgPaint.setColor(0xC0000000);
+    canvas->drawPaint(bgPaint);
+
+    SkPaint paint;
+    paint.setTextSize(16);
+    paint.setAntiAlias(true);
+    paint.setColor(0xFFFFFFFF);
+
+    SkPaint groupPaint;
+    groupPaint.setTextSize(18);
+    groupPaint.setUnderlineText(true);
+    groupPaint.setAntiAlias(true);
+    groupPaint.setColor(0xFFFFFFFF);
+
+    SkScalar x = SkIntToScalar(10);
+    SkScalar y = SkIntToScalar(10);
+
+    // Measure all key strings:
+    SkScalar keyWidth = 0;
+    for (Command& cmd : fCommands) {
+        keyWidth = SkMaxScalar(keyWidth,
+                               paint.measureText(cmd.fKeyName.c_str(), cmd.fKeyName.size()));
+    }
+    keyWidth += paint.measureText(" ", 1);
+
+    // If we're grouping by category, we'll be adding text height on every new group (including the
+    // first), so no need to do that here. Otherwise, skip down so the first line is where we want.
+    if (kGrouped_HelpMode != fHelpMode) {
+        y += paint.getTextSize();
+    }
+
+    // Print everything:
+    SkString lastGroup;
+    for (Command& cmd : fCommands) {
+        if (kGrouped_HelpMode == fHelpMode && lastGroup != cmd.fGroup) {
+            // Group change. Advance and print header:
+            y += paint.getTextSize();
+            canvas->drawText(cmd.fGroup.c_str(), cmd.fGroup.size(), x, y, groupPaint);
+            y += groupPaint.getTextSize() + 2;
+            lastGroup = cmd.fGroup;
+        }
+
+        canvas->drawText(cmd.fKeyName.c_str(), cmd.fKeyName.size(), x, y, paint);
+        SkString text = SkStringPrintf(": %s", cmd.fDescription.c_str());
+        canvas->drawText(text.c_str(), text.size(), x + keyWidth, y, paint);
+        y += paint.getTextSize() + 2;
+    }
+}
+
+}   // namespace sk_app