Touchpad: two-finger scroll and pinch zoom, fix selection row offset; v0.1.1

app/build.gradle

@@ -10,8 +10,8 @@ android {
         applicationId "xyz.whcself.whcshell"
         minSdk 26
         targetSdk 35
-        versionCode 1
-        versionName "0.1.0"
+        versionCode 2
+        versionName "0.1.1"
     }
 
     buildTypes {

app/src/main/java/xyz/whcself/whcshell/TermView.java

@@ -284,10 +284,15 @@ public final class TermView extends View {
         return Math.max(0, Math.min(cols - 1, c));
     }
 
+    /** Top of the first text row; the renderer starts rows below the padding by this offset. */
+    private int textTop() {
+        return getPaddingTop() + renderer.getFontLineSpacingAndAscent();
+    }
+
     /** Visible row, 0-based. */
     private int row(MotionEvent ev) {
         int rows = emulator().mRows;
-        int r = (int) Math.floor((ev.getY() - getPaddingTop()) / renderer.getFontLineSpacing());
+        int r = (int) Math.floor((ev.getY() - textTop()) / renderer.getFontLineSpacing());
         return Math.max(0, Math.min(rows - 1, r));
     }
 
@@ -448,6 +453,49 @@ public final class TermView extends View {
         return m;
     }
 
+    private float gestureY, pinchDist;
+
+    /**
+     * Touchpad gestures arrive as mouse-source events with a finger tool and no buttons: a fake
+     * finger classified as a two-finger swipe for scrolling (the gesture axes stay 0, so the finger's
+     * movement is the distance), two fake fingers for a pinch, and stray single-finger strokes around
+     * taps. None of them are button presses.
+     */
+    private boolean onTouchpadGesture(MotionEvent ev) {
+        int action = ev.getActionMasked();
+        if (ev.getPointerCount() >= 2) {
+            float d = (float) Math.hypot(ev.getX(0) - ev.getX(1), ev.getY(0) - ev.getY(1));
+            if (action == MotionEvent.ACTION_POINTER_DOWN) {
+                pinchDist = d;
+            } else if (action == MotionEvent.ACTION_MOVE && pinchDist > 0 && actions != null) {
+                if (d > pinchDist * 1.25f) {
+                    actions.zoom(1);
+                    pinchDist = d;
+                } else if (d < pinchDist / 1.25f) {
+                    actions.zoom(-1);
+                    pinchDist = d;
+                }
+            }
+            return true;
+        }
+        pinchDist = 0;
+        boolean swipe = android.os.Build.VERSION.SDK_INT >= 34
+            && ev.getClassification() == MotionEvent.CLASSIFICATION_TWO_FINGER_SWIPE;
+        if (action == MotionEvent.ACTION_DOWN) {
+            gestureY = ev.getY();
+            scrollAccum = 0;
+        } else if (action == MotionEvent.ACTION_MOVE && swipe) {
+            scrollAccum += (gestureY - ev.getY()) / renderer.getFontLineSpacing();
+            gestureY = ev.getY();
+            int lines = (int) scrollAccum;
+            if (lines != 0) {
+                scrollAccum -= lines;
+                scrollLines(lines, ev);
+            }
+        }
+        return true;
+    }
+
     private static final int[][] BUTTONS = {
         {MotionEvent.BUTTON_PRIMARY, TerminalEmulator.MOUSE_LEFT_BUTTON},
         {MotionEvent.BUTTON_TERTIARY, 1},
@@ -459,11 +507,12 @@ public final class TermView extends View {
      * button, so presses and releases are derived from changes in the button state.
      */
     private boolean onMouse(MotionEvent ev) {
+        if (ev.getToolType(0) == MotionEvent.TOOL_TYPE_FINGER) return onTouchpadGesture(ev);
         TerminalEmulator e = emulator();
         int action = ev.getActionMasked();
         int state = ev.getButtonState()
             & (MotionEvent.BUTTON_PRIMARY | MotionEvent.BUTTON_SECONDARY | MotionEvent.BUTTON_TERTIARY);
-        // Touchpad taps and injected events can come as DOWN/UP without any button state.
+        // Injected events (adb input mouse) come as DOWN/UP without any button state.
         if (action == MotionEvent.ACTION_DOWN && state == 0) implicitPrimary = true;
         if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) implicitPrimary = false;
         if (implicitPrimary) state |= MotionEvent.BUTTON_PRIMARY;
@@ -524,8 +573,8 @@ public final class TermView extends View {
         } else if (selDragging && (state & MotionEvent.BUTTON_PRIMARY) != 0
             && action == MotionEvent.ACTION_MOVE) {
             float y = ev.getY();
-            if (y < getPaddingTop()) scrollTranscript(-1);
-            else if (y > getHeight() - getPaddingBottom()) scrollTranscript(1);
+            if (y < textTop()) scrollTranscript(-1);
+            else if (y >= textTop() + emulator().mRows * renderer.getFontLineSpacing()) scrollTranscript(1);
             extendSelection(col, row + topRow);
         }
         if ((released & MotionEvent.BUTTON_PRIMARY) != 0 && selDragging) {