Enable pinch to change font size

Standard way of changing the font size on touch screen devices. It can
be easily and flexibly handled (e.g. with changing lighting
conditions) and doesn't interfere with volume settings nor with
selecting text. Two finger touches are reliably distinguished from one
finger long presses.

Resolves connectbot#430

app/src/main/java/org/connectbot/service/TerminalBridge.java

@@ -523,7 +523,7 @@ public synchronized void tryKeyVibrate() {
  *
  * @param sizeDp Size of font in dp
  */
- private void setFontSize(float sizeDp) {
+ public void setFontSize(float sizeDp) {
  if (sizeDp <= 0.0) {
  return;
  }
@@ -557,6 +557,13 @@ private void setFontSize(float sizeDp) {
  forcedSize = false;
  }
 
+ /**
+ * @return current text size in dp
+ */
+ public float getTextSizeDp() {
+ return getTextSizePx() / displayDensity / systemFontScale;
+ }
+
  /**
  * @return current text size in pixels
  */

app/src/main/java/org/connectbot/util/TerminalTextViewOverlay.java

@@ -35,6 +35,7 @@
 import android.view.MotionEvent;
 import android.view.inputmethod.EditorInfo;
 import android.view.inputmethod.InputConnection;
+import android.view.ScaleGestureDetector;
 import android.widget.TextView;
 import de.mud.terminal.VDUBuffer;
 import de.mud.terminal.vt320;
@@ -50,6 +51,7 @@ public class TerminalTextViewOverlay extends androidx.appcompat.widget.AppCompat
  private String currentSelection = "";
  private ActionMode selectionActionMode;
  private ClipboardManager clipboard;
+ private ScaleGestureDetector scaleDetector;
 
  private int oldBufferHeight = 0;
  private int oldScrollY = -1;
@@ -64,6 +66,9 @@ public TerminalTextViewOverlay(Context context, TerminalView terminalView) {
  setTypeface(Typeface.MONOSPACE);
  setTextIsSelectable(true);
  setCustomSelectionActionModeCallback(new TextSelectionActionModeCallback());
+
+ // Enable pinch to zoom
+ scaleDetector = new ScaleGestureDetector(context, new ScaleListener());
  }
 
  public void refreshTextFromBuffer() {
@@ -176,6 +181,8 @@ public void scrollTo(int x, int y) {
 
  @Override
  public boolean onTouchEvent(MotionEvent event) {
+ scaleDetector.onTouchEvent(event);
+
  if (event.getAction() == MotionEvent.ACTION_DOWN) {
  // Selection may be beginning. Sync the TextView with the buffer.
  refreshTextFromBuffer();
@@ -386,4 +393,22 @@ public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
  public void onDestroyActionMode(ActionMode mode) {
  }
  }
+
+ @Override
+ public boolean bringPointIntoView(int offset) {
+ return true;
+ }
+
+ private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
+ @Override
+ public boolean onScale(ScaleGestureDetector detector) {
+ terminalView.bridge.setFontSize(terminalView.bridge.getTextSizeDp() * detector.getScaleFactor());
+ return true;
+ }
+
+ @Override
+ public void onScaleEnd(ScaleGestureDetector detector) {
+ refreshTextFromBuffer();
+ }
+ }
 }