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Changed behaviour of pinch and quickzoom gestures as image reaches ed…
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…ge of screen for smoother zoom. Restructured debug.
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@davemorrissey
davemorrissey committed Nov 5, 2016
1 parent 41c5d10 commit 4505d63
Showing 1 changed file with 67 additions and 29 deletions.
96 changes: 67 additions & 29 deletions library/src/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
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Original file line number Diff line number Diff line change
Expand Up @@ -240,10 +240,11 @@ public class SubsamplingScaleImageView extends View {

// Current quickscale state
private final float quickScaleThreshold;
private PointF quickScaleCenter;
private float quickScaleLastDistance;
private PointF quickScaleLastPoint;
private boolean quickScaleMoved;
private PointF quickScaleVLastPoint;
private PointF quickScaleSCenter;
private PointF quickScaleVStart;

// Scale and center animation tracking
private Anim anim;
Expand Down Expand Up @@ -469,10 +470,11 @@ private void reset(boolean newImage) {
fullImageSampleSize = 0;
vCenterStart = null;
vDistStart = 0;
quickScaleCenter = null;
quickScaleLastDistance = 0f;
quickScaleLastPoint = null;
quickScaleMoved = false;
quickScaleSCenter = null;
quickScaleVLastPoint = null;
quickScaleVStart = null;
anim = null;
satTemp = null;
matrix = null;
Expand Down Expand Up @@ -552,9 +554,10 @@ public boolean onDoubleTap(MotionEvent e) {
scaleStart = scale;
isQuickScaling = true;
isZooming = true;
quickScaleCenter = viewToSourceCoord(vCenterStart);
quickScaleLastDistance = -1F;
quickScaleLastPoint = new PointF(quickScaleCenter.x, quickScaleCenter.y);
quickScaleSCenter = viewToSourceCoord(vCenterStart);
quickScaleVStart = new PointF(e.getX(), e.getY());
quickScaleVLastPoint = new PointF(quickScaleSCenter.x, quickScaleSCenter.y);
quickScaleMoved = false;
// We need to get events in onTouchEvent after this.
return false;
Expand Down Expand Up @@ -704,6 +707,7 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
isPanning = true;
consumed = true;

double previousScale = scale;
scale = Math.min(maxScale, (vDistEnd / vDistStart) * scaleStart);

if (scale <= minScale()) {
Expand All @@ -721,6 +725,13 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
float vTopNow = vTopStart * (scale/scaleStart);
vTranslate.x = vCenterEndX - vLeftNow;
vTranslate.y = vCenterEndY - vTopNow;
if ((previousScale * sHeight() < getHeight() && scale * sHeight() >= getHeight()) || (previousScale * sWidth() < getWidth() && scale * sWidth() >= getWidth())) {
fitToBounds(true);
vCenterStart.set(vCenterEndX, vCenterEndY);
vTranslateStart.set(vTranslate);
scaleStart = scale;
vDistStart = vDistEnd;
}
} else if (sRequestedCenter != null) {
// With a center specified from code, zoom around that point.
vTranslate.x = (getWidth()/2) - (scale * sRequestedCenter.x);
Expand All @@ -737,13 +748,15 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
} else if (isQuickScaling) {
// One finger zoom
// Stole Google's Magical Formula™ to make sure it feels the exact same
float dist = Math.abs(vCenterStart.y - event.getY()) * 2 + quickScaleThreshold;
float dist = Math.abs(quickScaleVStart.y - event.getY()) * 2 + quickScaleThreshold;

if (quickScaleLastDistance == -1F) quickScaleLastDistance = dist;
boolean isUpwards = event.getY() > quickScaleLastPoint.y;
quickScaleLastPoint.set(0, event.getY());
if (quickScaleLastDistance == -1f) {
quickScaleLastDistance = dist;
}
boolean isUpwards = event.getY() > quickScaleVLastPoint.y;
quickScaleVLastPoint.set(0, event.getY());

float spanDiff = (Math.abs(1 - (dist / quickScaleLastDistance)) * 0.5F);
float spanDiff = Math.abs(1 - (dist / quickScaleLastDistance)) * 0.5f;

if (spanDiff > 0.03f || quickScaleMoved) {
quickScaleMoved = true;
Expand All @@ -753,6 +766,7 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
multiplier = isUpwards ? (1 + spanDiff) : (1 - spanDiff);
}

double previousScale = scale;
scale = Math.max(minScale(), Math.min(maxScale, scale * multiplier));

if (panEnabled) {
Expand All @@ -762,6 +776,13 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
float vTopNow = vTopStart * (scale/scaleStart);
vTranslate.x = vCenterStart.x - vLeftNow;
vTranslate.y = vCenterStart.y - vTopNow;
if ((previousScale * sHeight() < getHeight() && scale * sHeight() >= getHeight()) || (previousScale * sWidth() < getWidth() && scale * sWidth() >= getWidth())) {
fitToBounds(true);
vCenterStart.set(sourceToViewCoord(quickScaleSCenter));
vTranslateStart.set(vTranslate);
scaleStart = scale;
dist = 0;
}
} else if (sRequestedCenter != null) {
// With a center specified from code, zoom around that point.
vTranslate.x = (getWidth()/2) - (scale * sRequestedCenter.x);
Expand Down Expand Up @@ -830,7 +851,7 @@ private boolean onTouchEventInternal(@NonNull MotionEvent event) {
if (isQuickScaling) {
isQuickScaling = false;
if (!quickScaleMoved) {
doubleTapZoom(quickScaleCenter, vCenterStart);
doubleTapZoom(quickScaleSCenter, vCenterStart);
}
}
if (maxTouchCount > 0 && (isZooming || isPanning)) {
Expand Down Expand Up @@ -1021,23 +1042,6 @@ protected void onDraw(Canvas canvas) {
}
}

if (debug) {
canvas.drawText("Scale: " + String.format(Locale.ENGLISH, "%.2f", scale), 5, 15, debugPaint);
canvas.drawText("Translate: " + String.format(Locale.ENGLISH, "%.2f", vTranslate.x) + ":" + String.format(Locale.ENGLISH, "%.2f", vTranslate.y), 5, 35, debugPaint);
PointF center = getCenter();
canvas.drawText("Source center: " + String.format(Locale.ENGLISH, "%.2f", center.x) + ":" + String.format(Locale.ENGLISH, "%.2f", center.y), 5, 55, debugPaint);

if (anim != null) {
PointF vCenterStart = sourceToViewCoord(anim.sCenterStart);
PointF vCenterEndRequested = sourceToViewCoord(anim.sCenterEndRequested);
PointF vCenterEnd = sourceToViewCoord(anim.sCenterEnd);
canvas.drawCircle(vCenterStart.x, vCenterStart.y, 10, debugPaint);
canvas.drawCircle(vCenterEndRequested.x, vCenterEndRequested.y, 20, debugPaint);
canvas.drawCircle(vCenterEnd.x, vCenterEnd.y, 25, debugPaint);
canvas.drawCircle(getWidth() / 2, getHeight() / 2, 30, debugPaint);
}
}

} else if (bitmap != null) {

float xScale = scale, yScale = scale;
Expand Down Expand Up @@ -1069,6 +1073,40 @@ protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, matrix, bitmapPaint);

}

if (debug) {
canvas.drawText("Scale: " + String.format(Locale.ENGLISH, "%.2f", scale), 5, 15, debugPaint);
canvas.drawText("Translate: " + String.format(Locale.ENGLISH, "%.2f", vTranslate.x) + ":" + String.format(Locale.ENGLISH, "%.2f", vTranslate.y), 5, 35, debugPaint);
PointF center = getCenter();
canvas.drawText("Source center: " + String.format(Locale.ENGLISH, "%.2f", center.x) + ":" + String.format(Locale.ENGLISH, "%.2f", center.y), 5, 55, debugPaint);
debugPaint.setStrokeWidth(2f);
if (anim != null) {
PointF vCenterStart = sourceToViewCoord(anim.sCenterStart);
PointF vCenterEndRequested = sourceToViewCoord(anim.sCenterEndRequested);
PointF vCenterEnd = sourceToViewCoord(anim.sCenterEnd);
canvas.drawCircle(vCenterStart.x, vCenterStart.y, 10, debugPaint);
debugPaint.setColor(Color.RED);
canvas.drawCircle(vCenterEndRequested.x, vCenterEndRequested.y, 20, debugPaint);
debugPaint.setColor(Color.BLUE);
canvas.drawCircle(vCenterEnd.x, vCenterEnd.y, 25, debugPaint);
debugPaint.setColor(Color.CYAN);
canvas.drawCircle(getWidth() / 2, getHeight() / 2, 30, debugPaint);
}
if (vCenterStart != null) {
debugPaint.setColor(Color.RED);
canvas.drawCircle(vCenterStart.x, vCenterStart.y, 20, debugPaint);
}
if (quickScaleSCenter != null) {
debugPaint.setColor(Color.BLUE);
canvas.drawCircle(sourceToViewX(quickScaleSCenter.x), sourceToViewY(quickScaleSCenter.y), 35, debugPaint);
}
if (quickScaleVStart != null) {
debugPaint.setColor(Color.CYAN);
canvas.drawCircle(quickScaleVStart.x, quickScaleVStart.y, 30, debugPaint);
}
debugPaint.setColor(Color.MAGENTA);
debugPaint.setStrokeWidth(1f);
}
}

/**
Expand Down

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