android.graphics.Canvas#save ( )源码实例Demo

@Override
public void draw(Canvas canvas, Position position) {
    canvas.drawPath(mPath, (flags & SELECTED) != 0
            ? mSelectedPaint : mBackgroundPaint);
    canvas.drawPath(mPath, (flags & SELECTED) != 0
            ? mSelectedPaint : mOutlinePaint);

    if (mView != null) {
        int state = canvas.save();
        canvas.translate(mView.getLeft(), mView.getTop());
        // keep icons "upright" if we get displayed on TOP position
        if (position != Position.TOP) {
            canvas.rotate(mStart + mSweep / 2 - 270);
        } else {
            canvas.rotate(mStart + mSweep / 2 - 90);
        }
        canvas.translate(-mView.getWidth() / 2, -mView.getHeight() / 2);

        mView.draw(canvas);
        canvas.restoreToCount(state);
    }
}
 

void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) {
	final int height = drawable.getMinimumHeight();

	canvas.save();
	canvas.clipRect(bounds);

	final int span = bounds.bottom - bounds.top;
	if (span < height) {
		bounds.top = bounds.bottom - height;
	}

	drawable.setBounds(bounds);
	drawable.draw(canvas);

	canvas.restore();
}
 

@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {

    if (mPinnedHeaderView != null) {
        c.save();

        mItemTouchListener.invalidTopAndBottom(mPinnedHeaderOffset);

        mClipBounds.top = mRecyclerViewPaddingTop + mHeaderTopMargin;
        // 锁定画布绘制范围，记为B
        // REVERSE_DIFFERENCE，实际上就是求得的B和A的差集范围，即B－A，只有在此范围内的绘制内容才会被显示
        // 因此,只绘制(0,0,parent.getWidth(),belowView.getTop())这个范围，然后画布移动了mPinnedHeaderTop，所以刚好是绘制顶部标签移动的范围
        // 低版本不行，换回Region.Op.UNION并集
        c.clipRect(mClipBounds, Region.Op.UNION);
        c.translate(mRecyclerViewPaddingLeft + mHeaderLeftMargin, mPinnedHeaderOffset + mRecyclerViewPaddingTop + mHeaderTopMargin);
        mPinnedHeaderView.draw(c);

        c.restore();
    }
}
 

@Override
public void draw(Canvas canvas, Matrix currentMatrix, float currentZoom, float
        currentRotateDegrees) {
    if (isVisible && bitmap != null) {
        canvas.save();
        float[] goal = {location.x, location.y};
        if (!autoScale) {
            currentMatrix.mapPoints(goal);
        } else {
            canvas.setMatrix(currentMatrix);
        }
        canvas.drawBitmap(bitmap, goal[0] - bitmap.getWidth() / 2,
                goal[1] - bitmap.getHeight() / 2, paint);
        canvas.restore();
    }
}
 

@Override
protected void onDraw(Canvas canvas)
{
    super.onDraw(canvas);
    //外圆
    canvas.drawCircle(getViewCenterX(), getViewCenterY(), mOuterRadius, mStrokePaint);

    //上方按钮
    canvas.drawRect(mBtnRectF, mFillPaint);
    canvas.drawRect(mBottomBtnRectF, mFillPaint);

    //右侧按钮
    canvas.save();
    canvas.rotate(45, getViewCenterX(), getViewCenterY());
    canvas.drawRect(mBottomBtnRectF, mFillPaint);
    canvas.restore();

    canvas.translate(0, 20);
}
 

@Override
protected void dispatchDraw (@NonNull Canvas canvas) {
    super.dispatchDraw(canvas);

    if (mIsDragging) {
        canvas.save();
        // Position the drag shadow.
        float posY = mTouchY - (float)mDragShadow.getMeasuredHeight() / 2f;
        canvas.translate(0, posY);
        mDragShadow.draw(canvas);
        canvas.restore();
    }
}
 

@Override
public void draw(Canvas canvas) {
  canvas.save();
  canvas.rotate(mRotation, getBounds().centerX(), getBounds().centerY());
  super.draw(canvas);
  canvas.restore();
}
 

@Override protected void onDraw(@NonNull Canvas canvas) {
    int saveCount = canvas.save();
    if (mEnableDraweeMatrix) {
        canvas.concat(mAttacher.getDrawMatrix());
    }
    super.onDraw(canvas);
    canvas.restoreToCount(saveCount);
}
 

public void onPreDraw(@NonNull Canvas canvas) {
    if (isClipping) {
        canvas.save();

        if (State.equals(clipRotation, 0f)) {
            canvas.clipRect(clipRect);
        } else {
            // Note, that prior Android 4.3 (18) canvas matrix is not correctly applied to
            // clip rect, clip rect will be set to its upper bound, which is good enough for us.
            canvas.rotate(clipRotation, clipRect.centerX(), clipRect.centerY());
            canvas.clipRect(clipRect);
            canvas.rotate(-clipRotation, clipRect.centerX(), clipRect.centerY());
        }
    }
}
 

private void drawTopEdge(DepthLayout dl, Canvas canvas, float[] src) {

    float[] dst = new float[] {
        dl.getTopLeft().x, dl.getTopLeft().y, dl.getTopRight().x, dl.getTopRight().y,
        dl.getTopRightBack().x, dl.getTopRightBack().y, dl.getTopLeftBack().x, dl.getTopLeftBack().y
    };
    int count = canvas.save();
    matrix.setPolyToPoly(src, 0, dst, 0, src.length >> 1);
    canvas.concat(matrix);
    drawRectancle(dl, canvas);
    drawShadow(dl.getTopLeft(), dl.getTopRight(), -180f, canvas, dl);
    canvas.restoreToCount(count);
  }
 

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    if(mStaticLayout != null){
        canvas.save();
        canvas.translate(getPaddingLeft(), getPaddingTop());
        mStaticLayout.draw(canvas);
        canvas.restore();
    }
}
 

void plotBarThick(Canvas c, double[] y_value, double[] x_values, int i_begin, int i_end, double x_inc, Paint linePainter) {
        if (tmpLineXY.length < 4*(y_value.length)) {
            Log.d(TAG, "plotBar(): new tmpLineXY");
            tmpLineXY = new float[4*(y_value.length)];
        }

        final double minYCanvas = axisY.pixelNoZoomFromV(AnalyzerGraphic.minDB);
        int pixelStep = 2;  // each bar occupy this virtual pixel
        c.save();
        matrix.reset();
        double extraPixelAlignOffset = 0.0f;
//        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
//          // There is an shift for Android 4.4, while no shift for Android 2.3
//          // I guess that is relate to GL ES acceleration
//          if (c.isHardwareAccelerated()) {
//            extraPixelAlignOffset = 0.5f;
//          }
//        }
        matrix.setTranslate((float)(-axisX.getShift() * (y_value.length - 1) * pixelStep - extraPixelAlignOffset),
                (float)(-axisY.getShift() * axisY.nCanvasPixel));
        matrix.postScale((float)(axisX.nCanvasPixel / ((axisX.vMaxInView() - axisX.vMinInView()) / x_inc * pixelStep)), (float)axisY.getZoom());
        c.concat(matrix);
        // fill interval same as canvas pixel width.
        for (int i = i_begin; i < i_end; i++) {
            float x = x_values == null ? i * pixelStep : (float)(x_values[i] / x_inc * pixelStep);
            float y = (float)axisY.pixelNoZoomFromV(clampDB(y_value[i]));
            tmpLineXY[4*i  ] = x;
            tmpLineXY[4*i+1] = (float)minYCanvas;
            tmpLineXY[4*i+2] = x;
            tmpLineXY[4*i+3] = y;
        }
        c.drawLines(tmpLineXY, 4*i_begin, 4*(i_end-i_begin), linePainter);
        c.restore();
    }
 

/** Draws the graphics based on the progress indicator's properties and the animation states. */
@Override
public void draw(@NonNull Canvas canvas) {
  Rect clipBounds = new Rect();

  if (getBounds().isEmpty() || !isVisible() || !canvas.getClipBounds(clipBounds)) {
    // Escape if bounds are empty, clip bounds are empty, or currently hidden.
    return;
  }

  canvas.save();
  drawingDelegate.adjustCanvas(canvas, progressIndicator, getGrowFraction());

  float displayedIndicatorWidth = progressIndicator.getIndicatorWidth() * getGrowFraction();
  float displayedRoundedCornerRadius =
      progressIndicator.getIndicatorCornerRadius() * getGrowFraction();

  // Draws the track first as the bottom layer.
  drawingDelegate.fillTrackWithColor(
      canvas,
      paint,
      combinedTrackColor,
      0f,
      1f,
      displayedIndicatorWidth,
      displayedRoundedCornerRadius);
  // Draws the indicators.
  for (int segmentIndex = 0;
      segmentIndex < animatorDelegate.segmentColors.length;
      segmentIndex++) {
    drawingDelegate.fillTrackWithColor(
        canvas,
        paint,
        animatorDelegate.segmentColors[segmentIndex],
        animatorDelegate.segmentPositions[2 * segmentIndex],
        animatorDelegate.segmentPositions[2 * segmentIndex + 1],
        displayedIndicatorWidth,
        displayedRoundedCornerRadius);
  }
}
 

@Override
public void drawAppName(Canvas canvas, float fraction, String name, int colorOfAppName,
                        WidthAndHeightOfView widthAndHeightOfView) {
    canvas.save();
    int width = widthAndHeightOfView.getWidth();
    int height = widthAndHeightOfView.getHeight();
    Paint paint = new Paint();
    paint.setColor(colorOfAppName);
    paint.setTextAlign(Paint.Align.CENTER);
    paint.setTextSize(50);
    canvas.drawText(name, width / 2, height / 2 + 50, paint);
    canvas.restore();
}
 

@Override
public void draw(Canvas c) {
    final Rect bounds = getBounds();
    final int saveCount = c.save();
    c.rotate(mRotation, bounds.exactCenterX(), bounds.exactCenterY());
    mRing.draw(c, bounds);
    c.restoreToCount(saveCount);
}
 

/**
 * 绘制Boss机体
 *
 * @param canvas
 */
private void drawBoss(Canvas canvas) {
    // 极限状态
    if (isLimit) {
        int y = (int) (currentFrame * object_height);
        canvas.save();
        canvas.clipRect(object_x, object_y,
                object_x + object_width, object_y + object_height);
        canvas.drawBitmap(bossPlane_crazy, object_x, object_y - y,
                paint);
        canvas.restore();
        currentFrame++;
        if (currentFrame >= 2) {
            currentFrame = 0;
        }

    }

    // 疯狂状态
    else if (isCrazy) {
        canvas.save();
        canvas.clipRect(object_x, object_y,
                object_x + object_width, object_y + object_height);
        canvas.drawBitmap(bossPlane_crazy, object_x, object_y
                - object_height, paint);
        canvas.restore();
    }

    // 愤怒状态
    else if (isAnger) {
        canvas.save();
        canvas.clipRect(object_x, object_y,
                object_x + object_width, object_y + object_height);
        canvas.drawBitmap(boosPlane, object_x, object_y
                - object_height, paint);
        canvas.restore();

    }

    // 普通状态
    else {
        canvas.save();
        canvas.clipRect(object_x, object_y,
                object_x + object_width, object_y + object_height);
        canvas.drawBitmap(boosPlane, object_x, object_y, paint);
        canvas.restore();
    }

    logic();
    shoot(canvas); // 射击
}
 

/**
 * 绘制悬浮组
 *
 * @param c      Canvas
 * @param parent RecyclerView
 */
protected void onDrawOverGroup(Canvas c, RecyclerView parent) {
    int firstVisiblePosition = ((LinearLayoutManager) parent.getLayoutManager()).findFirstVisibleItemPosition();
    if (firstVisiblePosition == RecyclerView.NO_POSITION) {
        return;
    }
    Group group = getCroup(firstVisiblePosition);
    if (group == null)
        return;
    String groupTitle = group.toString();
    if (TextUtils.isEmpty(groupTitle)) {
        return;
    }
    boolean isRestore = false;
    Group nextGroup = getCroup(firstVisiblePosition + 1);
    if (nextGroup != null && !group.equals(nextGroup)) {
        //说明是当前组最后一个元素，但不一定碰撞了
        View child = parent.findViewHolderForAdapterPosition(firstVisiblePosition).itemView;
        if (child.getTop() + child.getMeasuredHeight() < mGroupHeight) {
            //进一步检测碰撞
            c.save();//保存画布当前的状态
            isRestore = true;
            c.translate(0, child.getTop() + child.getMeasuredHeight() - mGroupHeight);
        }
    }
    int left = parent.getPaddingLeft();
    int right = parent.getWidth() - parent.getPaddingRight();
    int top = parent.getPaddingTop();
    int bottom = top + mGroupHeight;
    c.drawRect(left, top, right, bottom, mBackgroundPaint);
    float x;
    float y = top + mTextBaseLine;
    if (isCenter) {
        x = parent.getMeasuredWidth() / 2 - getTextX(groupTitle);
    } else {
        x = mPaddingLeft;
    }
    c.drawText(groupTitle, x, y, mTextPaint);
    if (isRestore) {
        //还原画布为初始状态
        c.restore();
    }
}
 

@Override
protected void onDraw(Canvas c) {
    if (isDismissed || outerCircleCenter == null) return;

    if (topBoundary > 0 && bottomBoundary > 0) {
        c.clipRect(0, topBoundary, getWidth(), bottomBoundary);
    }

    if (dimColor != -1) {
        c.drawColor(dimColor);
    }

    int saveCount;
    outerCirclePaint.setAlpha(outerCircleAlpha);
    if (shouldDrawShadow && outlineProvider == null) {
        saveCount = c.save();
        {
            c.clipPath(outerCirclePath, Region.Op.DIFFERENCE);
            drawJitteredShadow(c);
        }
        c.restoreToCount(saveCount);
    }
    c.drawCircle(outerCircleCenter[0], outerCircleCenter[1], outerCircleRadius, outerCirclePaint);

    targetCirclePaint.setAlpha(targetCircleAlpha);
    if (targetCirclePulseAlpha > 0) {
        targetCirclePulsePaint.setAlpha(targetCirclePulseAlpha);
        c.drawCircle(targetBounds.centerX(), targetBounds.centerY(),
                targetCirclePulseRadius, targetCirclePulsePaint);
    }
    c.drawCircle(targetBounds.centerX(), targetBounds.centerY(),
            targetCircleRadius, targetCirclePaint);

    saveCount = c.save();
    {
        c.translate(textBounds.left, textBounds.top);
        titlePaint.setAlpha(textAlpha);
        if (titleLayout != null) {
            titleLayout.draw(c);
        }

        if (descriptionLayout != null && titleLayout != null) {
            c.translate(0, titleLayout.getHeight() + TEXT_SPACING);
            descriptionPaint.setAlpha((int) (0.54f * textAlpha));
            descriptionLayout.draw(c);
        }
    }
    c.restoreToCount(saveCount);

    saveCount = c.save();
    {
        if (tintedTarget != null) {
            c.translate(targetBounds.centerX() - tintedTarget.getWidth() / 2,
                    targetBounds.centerY() - tintedTarget.getHeight() / 2);
            c.drawBitmap(tintedTarget, 0, 0, targetCirclePaint);
        } else if (target.icon != null) {
            c.translate(targetBounds.centerX() - target.icon.getBounds().width() / 2,
                    targetBounds.centerY() - target.icon.getBounds().height() / 2);
            target.icon.setAlpha(targetCirclePaint.getAlpha());
            target.icon.draw(c);
        }
    }
    c.restoreToCount(saveCount);

    if (debug) {
        drawDebugInformation(c);
    }
}
 

@Override
protected void draw(Canvas canvas, Rect bounds) {
    int saveCount = canvas.save();

    RectF arcBounds = mTempBounds;
    arcBounds.set(bounds);
    arcBounds.inset(mStrokeXInset, mStrokeYInset);

    mCurrentProgressBounds.set(arcBounds.left, arcBounds.bottom - 2 * mCenterRadius,
            arcBounds.right, arcBounds.bottom);

    //draw loading drawable
    mLoadingDrawable.setBounds((int) arcBounds.centerX() - mLoadingDrawable.getIntrinsicWidth() / 2,
            0,
            (int) arcBounds.centerX() + mLoadingDrawable.getIntrinsicWidth() / 2,
            mLoadingDrawable.getIntrinsicHeight());
    mLoadingDrawable.draw(canvas);

    //draw progress background
    float progressInset = mCenterRadius - mProgressCenterRadius;
    RectF progressRect = new RectF(mCurrentProgressBounds);
    //sub DEFAULT_STROKE_INTERVAL, otherwise will have a interval between progress background and progress outline
    progressRect.inset(progressInset - DEFAULT_STROKE_INTERVAL, progressInset - DEFAULT_STROKE_INTERVAL);
    mPaint.setColor(mProgressBgColor);
    mPaint.setStyle(Paint.Style.FILL);
    canvas.drawRoundRect(progressRect, mProgressCenterRadius, mProgressCenterRadius, mPaint);

    //draw progress
    mPaint.setColor(mProgressColor);
    mPaint.setStyle(Paint.Style.FILL);
    canvas.drawPath(createProgressPath(mProgress, mProgressCenterRadius, progressRect), mPaint);

    //draw leaves
    for (int i = 0; i < mLeafHolders.size(); i++) {
        int leafSaveCount = canvas.save();
        LeafHolder leafHolder = mLeafHolders.get(i);
        Rect leafBounds = leafHolder.mLeafRect;

        canvas.rotate(leafHolder.mLeafRotation, leafBounds.centerX(), leafBounds.centerY());
        mLeafDrawable.setBounds(leafBounds);
        mLeafDrawable.draw(canvas);

        canvas.restoreToCount(leafSaveCount);
    }

    //draw progress background outline,
    //after drawing the leaves and then draw the outline of the progress background can
    //prevent the leaves from flying to the outside
    RectF progressOutlineRect = new RectF(mCurrentProgressBounds);
    float progressOutlineStrokeInset = (mCenterRadius - mProgressCenterRadius) / 2.0f;
    progressOutlineRect.inset(progressOutlineStrokeInset, progressOutlineStrokeInset);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setColor(mProgressBgColor);
    mPaint.setStrokeWidth(mCenterRadius - mProgressCenterRadius);
    canvas.drawRoundRect(progressOutlineRect, mCenterRadius, mCenterRadius, mPaint);

    //draw electric fan outline
    float electricFanCenterX = arcBounds.right - mCenterRadius;
    float electricFanCenterY = arcBounds.bottom - mCenterRadius;

    mPaint.setColor(mElectricFanOutlineColor);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(mStrokeWidth);
    canvas.drawCircle(arcBounds.right - mCenterRadius, arcBounds.bottom - mCenterRadius,
            mCenterRadius - mStrokeWidth / 2.0f, mPaint);

    //draw electric background
    mPaint.setColor(mElectricFanBgColor);
    mPaint.setStyle(Paint.Style.FILL);
    canvas.drawCircle(arcBounds.right - mCenterRadius, arcBounds.bottom - mCenterRadius,
            mCenterRadius - mStrokeWidth + DEFAULT_STROKE_INTERVAL, mPaint);

    //draw electric fan
    int rotateSaveCount = canvas.save();
    canvas.rotate(mRotation, electricFanCenterX, electricFanCenterY);
    mElectricFanDrawable.setBounds((int) (electricFanCenterX - mElectricFanDrawable.getIntrinsicWidth() / 2 * mScale),
            (int) (electricFanCenterY - mElectricFanDrawable.getIntrinsicHeight() / 2 * mScale),
            (int) (electricFanCenterX + mElectricFanDrawable.getIntrinsicWidth() / 2 * mScale),
            (int) (electricFanCenterY + mElectricFanDrawable.getIntrinsicHeight() / 2 * mScale));
    mElectricFanDrawable.draw(canvas);
    canvas.restoreToCount(rotateSaveCount);

    //draw 100% text
    if (mScale < 1.0f) {
        mPaint.setTextSize(mTextSize * (1 - mScale));
        mPaint.setColor(mElectricFanOutlineColor);
        Rect textRect = new Rect();
        mPaint.getTextBounds(PERCENTAGE_100, 0, PERCENTAGE_100.length(), textRect);
        canvas.drawText(PERCENTAGE_100, electricFanCenterX - textRect.width() / 2.0f,
                electricFanCenterY + textRect.height() / 2.0f, mPaint);
    }

    canvas.restoreToCount(saveCount);
}
 

/**
 * 绘制翻起页背面
 *
 * @param canvas
 * @param bitmap
 */
private void drawCurrentBackArea(Canvas canvas, Bitmap bitmap) {
    int i = (int) (mBezierStart1.x + mBezierControl1.x) / 2;
    float f1 = Math.abs(i - mBezierControl1.x);
    int i1 = (int) (mBezierStart2.y + mBezierControl2.y) / 2;
    float f2 = Math.abs(i1 - mBezierControl2.y);
    float f3 = Math.min(f1, f2);
    mPath1.reset();
    mPath1.moveTo(mBeziervertex2.x, mBeziervertex2.y);
    mPath1.lineTo(mBeziervertex1.x, mBeziervertex1.y);
    mPath1.lineTo(mBezierEnd1.x, mBezierEnd1.y);
    mPath1.lineTo(mTouch.x, mTouch.y);
    mPath1.lineTo(mBezierEnd2.x, mBezierEnd2.y);
    mPath1.close();
    GradientDrawable mFolderShadowDrawable;
    int left;
    int right;
    if (mIsRTandLB) {
        left = (int) (mBezierStart1.x - 1);
        right = (int) (mBezierStart1.x + f3 + 1);
        mFolderShadowDrawable = mFolderShadowDrawableLR;
    } else {
        left = (int) (mBezierStart1.x - f3 - 1);
        right = (int) (mBezierStart1.x + 1);
        mFolderShadowDrawable = mFolderShadowDrawableRL;
    }
    canvas.save();
    try {
        canvas.clipPath(mPath0);
        canvas.clipPath(mPath1, Region.Op.INTERSECT);
    } catch (Exception e) {
    }


    mPaint.setColorFilter(mColorMatrixFilter);

    float dis = (float) Math.hypot(mCornerX - mBezierControl1.x,
            mBezierControl2.y - mCornerY);
    float f8 = (mCornerX - mBezierControl1.x) / dis;
    float f9 = (mBezierControl2.y - mCornerY) / dis;
    mMatrixArray[0] = 1 - 2 * f9 * f9;
    mMatrixArray[1] = 2 * f8 * f9;
    mMatrixArray[3] = mMatrixArray[1];
    mMatrixArray[4] = 1 - 2 * f8 * f8;
    mMatrix.reset();
    mMatrix.setValues(mMatrixArray);
    mMatrix.preTranslate(-mBezierControl1.x, -mBezierControl1.y);
    mMatrix.postTranslate(mBezierControl1.x, mBezierControl1.y);
    canvas.drawBitmap(bitmap, mMatrix, mPaint);
    // canvas.drawBitmap(bitmap, mMatrix, null);
    mPaint.setColorFilter(null);
    canvas.rotate(mDegrees, mBezierStart1.x, mBezierStart1.y);
    mFolderShadowDrawable.setBounds(left, (int) mBezierStart1.y, right,
            (int) (mBezierStart1.y + mMaxLength));
    mFolderShadowDrawable.draw(canvas);
    canvas.restore();
}