Options to disable pan and zoom gestures
diff --git a/README.md b/README.md
index f839bf3..3d4415e 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,7 @@
* Pan while zooming
* Seamless switch between pan and zoom
* Fling momentum after panning
+* Options to disable pan and/or zoom gestures
#### Overridable event detection
* Supports `OnClickListener` and `OnLongClickListener`
diff --git a/library/res/values/attrs.xml b/library/res/values/attrs.xml
index 5ef45d1..8d7ad12 100644
--- a/library/res/values/attrs.xml
+++ b/library/res/values/attrs.xml
@@ -18,6 +18,8 @@
<declare-styleable name="SubsamplingScaleImageView">
<attr name="assetName" format="string"/>
+ <attr name="panEnabled" format="boolean"/>
+ <attr name="zoomEnabled" format="boolean"/>
</declare-styleable>
</resources>
\ No newline at end of file
diff --git a/library/src/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java b/library/src/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
index 5ee4b85..eb71db2 100644
--- a/library/src/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
+++ b/library/src/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
@@ -69,6 +69,10 @@
// Max scale allowed (prevent infinite zoom)
private float maxScale = 2F;
+ // Gesture detection settings
+ private boolean panEnabled = true;
+ private boolean zoomEnabled = true;
+
// Current scale and scale at start of zoom
private float scale;
private float scaleStart;
@@ -80,6 +84,7 @@
// Source coordinate to center on, used when new position is set externally before view is ready
private Float pendingScale;
private PointF sPendingCenter;
+ private PointF sRequestedCenter;
// Source image dimensions and orientation - dimensions relate to the unrotated image
private int sWidth;
@@ -90,8 +95,8 @@
private boolean isZooming;
// Is one-finger panning in progress
private boolean isPanning;
- // Is an press in progress
- private boolean isPressed;
+ // Max touches used in current gesture
+ private int maxTouchCount;
// Fling detector
private GestureDetector detector;
@@ -130,7 +135,7 @@
this.handler = new Handler(new Handler.Callback() {
public boolean handleMessage(Message message) {
if (message.what == MESSAGE_LONG_CLICK && onLongClickListener != null) {
- isPressed = false;
+ maxTouchCount = 0;
SubsamplingScaleImageView.super.setOnLongClickListener(onLongClickListener);
performLongClick();
SubsamplingScaleImageView.super.setOnLongClickListener(null);
@@ -141,7 +146,7 @@
this.detector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
- if (readySent && vTranslate != null && (Math.abs(e1.getX() - e2.getX()) > 50 || Math.abs(e1.getY() - e2.getY()) > 50) && (Math.abs(velocityX) > 500 || Math.abs(velocityY) > 500) && !isZooming) {
+ if (panEnabled && readySent && vTranslate != null && (Math.abs(e1.getX() - e2.getX()) > 50 || Math.abs(e1.getY() - e2.getY()) > 50) && (Math.abs(velocityX) > 500 || Math.abs(velocityY) > 500) && !isZooming) {
flingMomentum = new PointF(velocityX * 0.5f, velocityY * 0.5f);
flingFrom = new PointF(vTranslate.x, vTranslate.y);
flingStart = System.currentTimeMillis();
@@ -160,6 +165,12 @@
setImageAsset(assetName);
}
}
+ if (typedAttr.hasValue(styleable.SubsamplingScaleImageView_panEnabled)) {
+ setPanEnabled(typedAttr.getBoolean(styleable.SubsamplingScaleImageView_panEnabled, true));
+ }
+ if (typedAttr.hasValue(styleable.SubsamplingScaleImageView_zoomEnabled)) {
+ setZoomEnabled(typedAttr.getBoolean(styleable.SubsamplingScaleImageView_zoomEnabled, true));
+ }
}
}
@@ -240,9 +251,10 @@
vTranslateStart = null;
pendingScale = 0f;
sPendingCenter = null;
+ sRequestedCenter = null;
isZooming = false;
isPanning = false;
- isPressed = false;
+ maxTouchCount = 0;
fullImageSampleSize = 0;
vCenterStart = null;
vDistStart = 0;
@@ -343,15 +355,19 @@
case MotionEvent.ACTION_POINTER_1_DOWN:
case MotionEvent.ACTION_POINTER_2_DOWN:
getParent().requestDisallowInterceptTouchEvent(true);
- isPressed = true;
+ maxTouchCount = Math.max(maxTouchCount, touchCount);
if (touchCount >= 2) {
- // Start pinch to zoom. Calculate distance between touch points and center point of the pinch.
- float distance = distance(event.getX(0), event.getX(1), event.getY(0), event.getY(1));
- scaleStart = scale;
- vDistStart = distance;
- vTranslateStart = new PointF(vTranslate.x, vTranslate.y);
- vCenterStart = new PointF((event.getX(0) + event.getX(1))/2, (event.getY(0) + event.getY(1))/2);
-
+ if (zoomEnabled) {
+ // Start pinch to zoom. Calculate distance between touch points and center point of the pinch.
+ float distance = distance(event.getX(0), event.getX(1), event.getY(0), event.getY(1));
+ scaleStart = scale;
+ vDistStart = distance;
+ vTranslateStart = new PointF(vTranslate.x, vTranslate.y);
+ vCenterStart = new PointF((event.getX(0) + event.getX(1))/2, (event.getY(0) + event.getY(1))/2);
+ } else {
+ // Abort all gestures on second touch
+ maxTouchCount = 0;
+ }
// Cancel long click timer
handler.removeMessages(MESSAGE_LONG_CLICK);
} else {
@@ -365,33 +381,44 @@
return true;
case MotionEvent.ACTION_MOVE:
boolean consumed = false;
- if (isPressed) {
+ if (maxTouchCount > 0) {
if (touchCount >= 2) {
// Calculate new distance between touch points, to scale and pan relative to start values.
vDistEnd = distance(event.getX(0), event.getX(1), event.getY(0), event.getY(1));
vCenterEnd = new PointF((event.getX(0) + event.getX(1))/2, (event.getY(0) + event.getY(1))/2);
- if (distance(vCenterStart.x, vCenterEnd.x, vCenterStart.y, vCenterEnd.y) > 5 || Math.abs(vDistEnd - vDistStart) > 5 || isPanning) {
+ if (zoomEnabled && (distance(vCenterStart.x, vCenterEnd.x, vCenterStart.y, vCenterEnd.y) > 5 || Math.abs(vDistEnd - vDistStart) > 5 || isPanning)) {
isZooming = true;
isPanning = true;
consumed = true;
scale = Math.min(maxScale, (vDistEnd / vDistStart) * scaleStart);
- // Translate to place the source image coordinate that was at the center of the pinch at the start
- // at the center of the pinch now, to give simultaneous pan + zoom.
- float vLeftStart = vCenterStart.x - vTranslateStart.x;
- float vTopStart = vCenterStart.y - vTranslateStart.y;
- float vLeftNow = vLeftStart * (scale/scaleStart);
- float vTopNow = vTopStart * (scale/scaleStart);
- vTranslate.x = vCenterEnd.x - vLeftNow;
- vTranslate.y = vCenterEnd.y - vTopNow;
+ if (panEnabled) {
+ // Translate to place the source image coordinate that was at the center of the pinch at the start
+ // at the center of the pinch now, to give simultaneous pan + zoom.
+ float vLeftStart = vCenterStart.x - vTranslateStart.x;
+ float vTopStart = vCenterStart.y - vTranslateStart.y;
+ float vLeftNow = vLeftStart * (scale/scaleStart);
+ float vTopNow = vTopStart * (scale/scaleStart);
+ vTranslate.x = vCenterEnd.x - vLeftNow;
+ vTranslate.y = vCenterEnd.y - vTopNow;
+ } else if (sRequestedCenter != null) {
+ // With a center specified from code, zoom around that point.
+ vTranslate.x = (getWidth()/2) - (scale * sRequestedCenter.x);
+ vTranslate.y = (getHeight()/2) - (scale * sRequestedCenter.y);
+ } else {
+ // With no requested center, scale around the image center.
+ vTranslate.x = (getWidth()/2) - (scale * (sWidth()/2));
+ vTranslate.y = (getHeight()/2) - (scale * (sHeight()/2));
+ }
fitToBounds();
refreshRequiredTiles(false);
}
} else if (!isZooming) {
- // One finger pan - translate the image
+ // One finger pan - translate the image. We do this calculation even with pan disabled so click
+ // and long click behaviour is preserved.
float dx = Math.abs(event.getX() - vCenterStart.x);
float dy = Math.abs(event.getY() - vCenterStart.y);
if (dx > 5 || dy > 5 || isPanning) {
@@ -406,11 +433,17 @@
isPanning = true;
} else if (dx > 5) {
// Haven't panned the image, and we're at the left or right edge. Switch to page swipe.
- isPressed = false;
+ maxTouchCount = 0;
handler.removeMessages(MESSAGE_LONG_CLICK);
getParent().requestDisallowInterceptTouchEvent(false);
}
+ if (!panEnabled) {
+ vTranslate.x = vTranslateStart.x;
+ vTranslate.y = vTranslateStart.y;
+ getParent().requestDisallowInterceptTouchEvent(false);
+ }
+
refreshRequiredTiles(false);
}
}
@@ -425,7 +458,7 @@
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_POINTER_2_UP:
handler.removeMessages(MESSAGE_LONG_CLICK);
- if (isPressed && (isZooming || isPanning)) {
+ if (maxTouchCount > 0 && (isZooming || isPanning)) {
if (isZooming && touchCount == 2) {
// Convert from zoom to pan with remaining touch
isPanning = true;
@@ -443,16 +476,18 @@
if (touchCount < 2) {
// End panning when no touch points
isPanning = false;
+ maxTouchCount = 0;
}
// Trigger load of tiles now required
refreshRequiredTiles(true);
return true;
- } else if (isPressed) {
+ } else if (maxTouchCount == 1) {
performClick();
}
if (touchCount == 1) {
isZooming = false;
isPanning = false;
+ maxTouchCount = 0;
}
return true;
}
@@ -1083,6 +1118,7 @@
public void setScaleAndCenter(float scale, PointF sCenter) {
this.pendingScale = scale;
this.sPendingCenter = sCenter;
+ this.sRequestedCenter = sCenter;
invalidate();
}
@@ -1144,4 +1180,37 @@
return null;
}
+ /**
+ * Returns true if zoom gesture detection is enabled.
+ */
+ public boolean isZoomEnabled() {
+ return zoomEnabled;
+ }
+
+ /**
+ * Enable or disable zoom gesture detection. Disabling zoom locks the the current scale.
+ */
+ public void setZoomEnabled(boolean zoomEnabled) {
+ this.zoomEnabled = zoomEnabled;
+ }
+
+ /**
+ * Returns true if pan gesture detection is enabled.
+ */
+ public boolean isPanEnabled() {
+ return panEnabled;
+ }
+
+ /**
+ * Enable or disable pan gesture detection. Disabling pan causes the image to be centered.
+ */
+ public void setPanEnabled(boolean panEnabled) {
+ this.panEnabled = panEnabled;
+ if (!panEnabled && vTranslate != null) {
+ vTranslate.x = (getWidth()/2) - (scale * (sWidth()/2));
+ vTranslate.y = (getHeight()/2) - (scale * (sHeight()/2));
+ refreshRequiredTiles(true);
+ invalidate();
+ }
+ }
}
