// 记录缩放前的一些信息
private void saveScaleContext(float x1, float y1, float x2, float y2) {
mScaleBase = MathUtils.getMatrixScale(mOuterMatrix)[0] / MathUtils.getDistance(x1, y1, x2, y2);
// 获取缩放缩放点中点在第一层变换后的图片上的坐标
float[] center =
MathUtils.inverseMatrixPoint(MathUtils.getCenterPoint(x1, y1, x2, y2), mOuterMatrix);
mScaleCenter.set(center[0], center[1]);
}
// 当缩放操作结束如果不在正确位置用动画恢复
private void scaleEnd() {
// 不允许动画过程中再触发
if ((mScaleAnimator != null && mScaleAnimator.isRunning()) || getDrawable() == null) {
return;
}
// 是否修正了位置
boolean change = false;
// 获取图片整体的变换矩阵
Matrix currentMatrix = getCurrentImageMatrix();
// 整体缩放比例
float currentScale = MathUtils.getMatrixScale(currentMatrix)[0];
// 第二层缩放比例
float outerScale = MathUtils.getMatrixScale(mOuterMatrix)[0];
// 控件大小
float displayWidth = getMeasuredWidth();
float displayHeight = getMeasuredHeight();
float maxScale = getMaxScale();
// 比例修正
float scalePost = 1;
// 位置修正
float postX = 0;
float postY = 0;
// 如果整体缩放比例大于最大比例，进行缩放修正
if (currentScale > maxScale) {
scalePost = maxScale / currentScale;
}
// 如果缩放修正后整体导致第二层缩放小于1（就是图片比fit center状态还小），重新修正缩放
if (outerScale * scalePost < 1) {
scalePost = 1 / outerScale;
}
// 如果修正不为1，说明进行了修正
if (scalePost != 1) {
change = true;
}
// 尝试根据缩放点进行缩放修正
Matrix testMatrix = new Matrix(currentMatrix);
testMatrix.postScale(scalePost, scalePost, mLastMovePoint.x, mLastMovePoint.y);
RectF testBound =
new RectF(0, 0, getDrawable().getIntrinsicWidth(), getDrawable().getIntrinsicHeight());
// 获取缩放修正后的图片方框
testMatrix.mapRect(testBound);
// 检测缩放修正后位置有无超出，如果超出进行位置修正
if (testBound.right - testBound.left < displayWidth) {
postX = displayWidth / 2 - (testBound.right + testBound.left) / 2;
} else if (testBound.left > 0) {
postX = -testBound.left;
} else if (testBound.right < displayWidth) {
postX = displayWidth - testBound.right;
}
if (testBound.bottom - testBound.top < displayHeight) {
postY = displayHeight / 2 - (testBound.bottom + testBound.top) / 2;
} else if (testBound.top > 0) {
postY = -testBound.top;
} else if (testBound.bottom < displayHeight) {
postY = displayHeight - testBound.bottom;
}
// 如果位置修正不为0，说明进行了修正
if (postX != 0 || postY != 0) {
change = true;
}
// 只有有执行修正才执行动画
if (change) {
// 如果up的时候触发惯性，这里需要取消掉，以修正动画为主
if (mFlingAnimator != null) {
mFlingAnimator.cancel();
mFlingAnimator = null;
}
// 动画开始举证
Matrix animStart = new Matrix(mOuterMatrix);
// 计算结束举证
Matrix animEnd = new Matrix(mOuterMatrix);
animEnd.postScale(scalePost, scalePost, mLastMovePoint.x, mLastMovePoint.y);
animEnd.postTranslate(postX, postY);
// 启动矩阵动画
mScaleAnimator = new ScaleAnimator(animStart, animEnd);
mScaleAnimator.start();
}
}
// 双击后放大或者缩小
// 当当前缩放比例大于等于1，那么双击放大到MaxScale
// 当当前缩放比例小于1，双击放大到1
// 当当前缩放比例等于MaxScale，双击缩小到屏幕大小
private void doubleTap(float x, float y) {
// 不允许动画过程中再触发
if ((mScaleAnimator != null && mScaleAnimator.isRunning()) || getDrawable() == null) {
return;
}
// 获取第一层变换矩阵
Matrix innerMatrix = getInnerMatrix();
// 当前总的缩放比例
float innerScale = MathUtils.getMatrixScale(innerMatrix)[0];
float outerScale = MathUtils.getMatrixScale(mOuterMatrix)[0];
float currentScale = innerScale * outerScale;
// 控件大小
float displayWidth = getMeasuredWidth();
float displayHeight = getMeasuredHeight();
// 最大放大大小
float maxScale = getMaxScale();
// 接下来要放大的大小
float nextScale = calculateNextScale(innerScale, outerScale);
// 如果接下来放大大于最大值或者小于fit center值，则取边界
if (nextScale < innerScale) {
nextScale = innerScale;
} else if (nextScale > maxScale) {
nextScale = maxScale;
}
// 缩放动画初始矩阵为当前矩阵值
Matrix animStart = new Matrix(mOuterMatrix);
// 开始计算缩放动画的结果矩阵
Matrix animEnd = new Matrix(mOuterMatrix);
// 计算还需缩放的倍数
animEnd.postScale(nextScale / currentScale, nextScale / currentScale, x, y);
// 将放大点移动到控件中心
animEnd.postTranslate(displayWidth / 2 - x, displayHeight / 2 - y);
// 得到放大之后的图片方框
Matrix testMatrix = new Matrix(innerMatrix);
testMatrix.postConcat(animEnd);
RectF testBound =
new RectF(0, 0, getDrawable().getIntrinsicWidth(), getDrawable().getIntrinsicHeight());
testMatrix.mapRect(testBound);
// 修正位置
float postX = 0;
float postY = 0;
if (testBound.right - testBound.left < displayWidth) {
postX = displayWidth / 2 - (testBound.right + testBound.left) / 2;
} else if (testBound.left > 0) {
postX = -testBound.left;
} else if (testBound.right < displayWidth) {
postX = displayWidth - testBound.right;
}
if (testBound.bottom - testBound.top < displayHeight) {
postY = displayHeight / 2 - (testBound.bottom + testBound.top) / 2;
} else if (testBound.top > 0) {
postY = -testBound.top;
} else if (testBound.bottom < displayHeight) {
postY = displayHeight - testBound.bottom;
}
// 应用修正位置
animEnd.postTranslate(postX, postY);
// 如果正在执行惯性动画，则取消掉
if (mFlingAnimator != null) {
mFlingAnimator.cancel();
mFlingAnimator = null;
}
// 启动矩阵动画
mScaleAnimator = new ScaleAnimator(animStart, animEnd);
mScaleAnimator.start();
}