examples/mdoutliner: add Markdown Outliner example

.gitignore

@@ -6,4 +6,6 @@ cmd/handbindings/handbindings
 cmd/handbindings/bindings_test/direct
 cmd/handbindings/bindings_test/testapp
 cmd/genbindings/genbindings
+
 examples/helloworld/helloworld
+examples/mdoutliner/mdoutliner

examples/mdoutliner/main.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/mappu/miqt/qt"
+)
+
+const sampleContent = `# Markdown Outliner
+
+This is sample markdown content.
+
+## Features
+
+- You can use the outline on the left to jump to parts of the document
+- Demonstrates use of the MIQT library`
+
+type AppWindow struct {
+	w        *qt.QMainWindow
+	cw       *qt.QWidget
+	outline  *qt.QListWidget
+	textArea *qt.QTextEdit
+}
+
+func NewAppWindow() *AppWindow {
+
+	ret := AppWindow{}
+
+	ret.w = qt.NewQMainWindow()
+	ret.w.SetWindowTitle("Markdown Outliner")
+
+	// Menu
+
+	mnu := qt.NewQMenuBar()
+	fileMenu := mnu.AddMenuWithTitle("&File")
+	open := fileMenu.AddAction("Open...")
+	open.SetShortcut(qt.NewQKeySequence2("Ctrl+O"))
+	open.OnTriggered1(ret.handleFileOpen)
+	fileMenu.AddSeparator()
+	exit := fileMenu.AddAction("Exit")
+	exit.OnTriggered1(func() {
+		os.Exit(0)
+	})
+
+	helpMenu := mnu.AddMenuWithTitle("&Help")
+	aboutQt := helpMenu.AddAction("About Qt")
+	aboutQt.SetShortcut(qt.NewQKeySequence2("F1"))
+	aboutQt.OnTriggered1(func() {
+		qt.QApplication_AboutQt()
+	})
+	ret.w.SetMenuBar(mnu)
+
+	// Main widgets
+
+	ret.cw = qt.NewQWidget2(ret.w.QWidget)
+	ret.w.SetCentralWidget(ret.cw)
+	layout := qt.NewQHBoxLayout2(ret.cw)
+
+	panes := qt.NewQSplitter()
+	layout.AddWidget(panes.QWidget)
+
+	ret.outline = qt.NewQListWidget2(ret.cw)
+	panes.AddWidget(ret.outline.QWidget)
+	ret.outline.OnCurrentItemChanged(ret.handleJumpToBookmark)
+
+	ret.textArea = qt.NewQTextEdit3(ret.cw)
+	ret.textArea.OnTextChanged(ret.handleTextChanged)
+	ret.textArea.SetText(sampleContent)
+	panes.AddWidget(ret.textArea.QWidget)
+
+	panes.SetSizes([]int{250, 550})
+
+	return &ret
+}
+
+const lineNumberRole = 0x0100 // Qt::UserDataRole
+
+func (a *AppWindow) handleFileOpen() {
+	fname := qt.QFileDialog_GetOpenFileName4(a.w.QWidget, "Open markdown file...", "", "Markdown files (*.md *.txt);;All Files (*)")
+	if fname == "" {
+		return
+	}
+
+	contents, err := ioutil.ReadFile(fname)
+	if err != nil {
+		qt.QMessageBox_Warning(a.w.QWidget, "Failed to open file", fmt.Sprintf("Opening file %q: %v", fname, err))
+		return
+	}
+
+	a.textArea.SetText(string(contents))
+}
+
+func (a *AppWindow) handleTextChanged() {
+	content := a.textArea.ToPlainText()
+	a.updateOutlineForContent(content)
+}
+
+func (a *AppWindow) updateOutlineForContent(content string) {
+	a.outline.Clear()
+
+	lines := strings.Split(content, "\n")
+
+	for lineNumber, line := range lines {
+		if strings.HasPrefix(line, `#`) {
+
+			bookmark := qt.NewQListWidgetItem7(line, a.outline)
+			bookmark.SetData(lineNumberRole, qt.NewQVariant5(lineNumber))
+		}
+	}
+}
+
+func (a *AppWindow) handleJumpToBookmark() {
+	itm := a.outline.CurrentItem()
+	if itm == nil {
+		return
+	}
+
+	lineNumber := itm.Data(lineNumberRole).ToInt()
+
+	targetBlock := a.textArea.Document().FindBlockByLineNumber(lineNumber)
+	a.textArea.SetTextCursor(qt.NewQTextCursor4(targetBlock))
+
+	a.textArea.SetFocus()
+}
+
+func main() {
+	qt.NewQApplication(os.Args)
+
+	app := NewAppWindow()
+	app.w.Show()
+
+	qt.QApplication_Exec()
+}