michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkRRect.h"
michael@0: #include "SkMatrix.h"
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: void SkRRect::setRectXY(const SkRect& rect, SkScalar xRad, SkScalar yRad) {
michael@0:     if (rect.isEmpty()) {
michael@0:         this->setEmpty();
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     if (xRad <= 0 || yRad <= 0) {
michael@0:         // all corners are square in this case
michael@0:         this->setRect(rect);
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     if (rect.width() < xRad+xRad || rect.height() < yRad+yRad) {
michael@0:         SkScalar scale = SkMinScalar(SkScalarDiv(rect.width(), xRad + xRad),
michael@0:                                      SkScalarDiv(rect.height(), yRad + yRad));
michael@0:         SkASSERT(scale < SK_Scalar1);
michael@0:         xRad = SkScalarMul(xRad, scale);
michael@0:         yRad = SkScalarMul(yRad, scale);
michael@0:     }
michael@0: 
michael@0:     fRect = rect;
michael@0:     for (int i = 0; i < 4; ++i) {
michael@0:         fRadii[i].set(xRad, yRad);
michael@0:     }
michael@0:     fType = kSimple_Type;
michael@0:     if (xRad >= SkScalarHalf(fRect.width()) && yRad >= SkScalarHalf(fRect.height())) {
michael@0:         fType = kOval_Type;
michael@0:         // TODO: assert that all the x&y radii are already W/2 & H/2
michael@0:     }
michael@0: 
michael@0:     SkDEBUGCODE(this->validate();)
michael@0: }
michael@0: 
michael@0: void SkRRect::setRectRadii(const SkRect& rect, const SkVector radii[4]) {
michael@0:     if (rect.isEmpty()) {
michael@0:         this->setEmpty();
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     fRect = rect;
michael@0:     memcpy(fRadii, radii, sizeof(fRadii));
michael@0: 
michael@0:     bool allCornersSquare = true;
michael@0: 
michael@0:     // Clamp negative radii to zero
michael@0:     for (int i = 0; i < 4; ++i) {
michael@0:         if (fRadii[i].fX <= 0 || fRadii[i].fY <= 0) {
michael@0:             // In this case we are being a little fast & loose. Since one of
michael@0:             // the radii is 0 the corner is square. However, the other radii
michael@0:             // could still be non-zero and play in the global scale factor
michael@0:             // computation.
michael@0:             fRadii[i].fX = 0;
michael@0:             fRadii[i].fY = 0;
michael@0:         } else {
michael@0:             allCornersSquare = false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (allCornersSquare) {
michael@0:         this->setRect(rect);
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     // Proportionally scale down all radii to fit. Find the minimum ratio
michael@0:     // of a side and the radii on that side (for all four sides) and use
michael@0:     // that to scale down _all_ the radii. This algorithm is from the
michael@0:     // W3 spec (http://www.w3.org/TR/css3-background/) section 5.5 - Overlapping
michael@0:     // Curves:
michael@0:     // "Let f = min(Li/Si), where i is one of { top, right, bottom, left },
michael@0:     //   Si is the sum of the two corresponding radii of the corners on side i,
michael@0:     //   and Ltop = Lbottom = the width of the box,
michael@0:     //   and Lleft = Lright = the height of the box.
michael@0:     // If f < 1, then all corner radii are reduced by multiplying them by f."
michael@0:     SkScalar scale = SK_Scalar1;
michael@0: 
michael@0:     if (fRadii[0].fX + fRadii[1].fX > rect.width()) {
michael@0:         scale = SkMinScalar(scale,
michael@0:                             SkScalarDiv(rect.width(), fRadii[0].fX + fRadii[1].fX));
michael@0:     }
michael@0:     if (fRadii[1].fY + fRadii[2].fY > rect.height()) {
michael@0:         scale = SkMinScalar(scale,
michael@0:                             SkScalarDiv(rect.height(), fRadii[1].fY + fRadii[2].fY));
michael@0:     }
michael@0:     if (fRadii[2].fX + fRadii[3].fX > rect.width()) {
michael@0:         scale = SkMinScalar(scale,
michael@0:                             SkScalarDiv(rect.width(), fRadii[2].fX + fRadii[3].fX));
michael@0:     }
michael@0:     if (fRadii[3].fY + fRadii[0].fY > rect.height()) {
michael@0:         scale = SkMinScalar(scale,
michael@0:                             SkScalarDiv(rect.height(), fRadii[3].fY + fRadii[0].fY));
michael@0:     }
michael@0: 
michael@0:     if (scale < SK_Scalar1) {
michael@0:         for (int i = 0; i < 4; ++i) {
michael@0:             fRadii[i].fX = SkScalarMul(fRadii[i].fX, scale);
michael@0:             fRadii[i].fY = SkScalarMul(fRadii[i].fY, scale);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // At this point we're either oval, simple, or complex (not empty or rect)
michael@0:     // but we lazily resolve the type to avoid the work if the information
michael@0:     // isn't required.
michael@0:     fType = (SkRRect::Type) kUnknown_Type;
michael@0: 
michael@0:     SkDEBUGCODE(this->validate();)
michael@0: }
michael@0: 
michael@0: // This method determines if a point known to be inside the RRect's bounds is
michael@0: // inside all the corners.
michael@0: bool SkRRect::checkCornerContainment(SkScalar x, SkScalar y) const {
michael@0:     SkPoint canonicalPt; // (x,y) translated to one of the quadrants
michael@0:     int index;
michael@0: 
michael@0:     if (kOval_Type == this->type()) {
michael@0:         canonicalPt.set(x - fRect.centerX(), y - fRect.centerY());
michael@0:         index = kUpperLeft_Corner;  // any corner will do in this case
michael@0:     } else {
michael@0:         if (x < fRect.fLeft + fRadii[kUpperLeft_Corner].fX &&
michael@0:             y < fRect.fTop + fRadii[kUpperLeft_Corner].fY) {
michael@0:             // UL corner
michael@0:             index = kUpperLeft_Corner;
michael@0:             canonicalPt.set(x - (fRect.fLeft + fRadii[kUpperLeft_Corner].fX),
michael@0:                             y - (fRect.fTop + fRadii[kUpperLeft_Corner].fY));
michael@0:             SkASSERT(canonicalPt.fX < 0 && canonicalPt.fY < 0);
michael@0:         } else if (x < fRect.fLeft + fRadii[kLowerLeft_Corner].fX &&
michael@0:                    y > fRect.fBottom - fRadii[kLowerLeft_Corner].fY) {
michael@0:             // LL corner
michael@0:             index = kLowerLeft_Corner;
michael@0:             canonicalPt.set(x - (fRect.fLeft + fRadii[kLowerLeft_Corner].fX),
michael@0:                             y - (fRect.fBottom - fRadii[kLowerLeft_Corner].fY));
michael@0:             SkASSERT(canonicalPt.fX < 0 && canonicalPt.fY > 0);
michael@0:         } else if (x > fRect.fRight - fRadii[kUpperRight_Corner].fX &&
michael@0:                    y < fRect.fTop + fRadii[kUpperRight_Corner].fY) {
michael@0:             // UR corner
michael@0:             index = kUpperRight_Corner;
michael@0:             canonicalPt.set(x - (fRect.fRight - fRadii[kUpperRight_Corner].fX),
michael@0:                             y - (fRect.fTop + fRadii[kUpperRight_Corner].fY));
michael@0:             SkASSERT(canonicalPt.fX > 0 && canonicalPt.fY < 0);
michael@0:         } else if (x > fRect.fRight - fRadii[kLowerRight_Corner].fX &&
michael@0:                    y > fRect.fBottom - fRadii[kLowerRight_Corner].fY) {
michael@0:             // LR corner
michael@0:             index = kLowerRight_Corner;
michael@0:             canonicalPt.set(x - (fRect.fRight - fRadii[kLowerRight_Corner].fX),
michael@0:                             y - (fRect.fBottom - fRadii[kLowerRight_Corner].fY));
michael@0:             SkASSERT(canonicalPt.fX > 0 && canonicalPt.fY > 0);
michael@0:         } else {
michael@0:             // not in any of the corners
michael@0:             return true;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // A point is in an ellipse (in standard position) if:
michael@0:     //      x^2     y^2
michael@0:     //     ----- + ----- <= 1
michael@0:     //      a^2     b^2
michael@0:     // or :
michael@0:     //     b^2*x^2 + a^2*y^2 <= (ab)^2
michael@0:     SkScalar dist =  SkScalarMul(SkScalarSquare(canonicalPt.fX), SkScalarSquare(fRadii[index].fY)) +
michael@0:                      SkScalarMul(SkScalarSquare(canonicalPt.fY), SkScalarSquare(fRadii[index].fX));
michael@0:     return dist <= SkScalarSquare(SkScalarMul(fRadii[index].fX, fRadii[index].fY));
michael@0: }
michael@0: 
michael@0: bool SkRRect::allCornersCircular() const {
michael@0:     return fRadii[0].fX == fRadii[0].fY &&
michael@0:         fRadii[1].fX == fRadii[1].fY &&
michael@0:         fRadii[2].fX == fRadii[2].fY &&
michael@0:         fRadii[3].fX == fRadii[3].fY;
michael@0: }
michael@0: 
michael@0: bool SkRRect::contains(const SkRect& rect) const {
michael@0:     if (!this->getBounds().contains(rect)) {
michael@0:         // If 'rect' isn't contained by the RR's bounds then the
michael@0:         // RR definitely doesn't contain it
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (this->isRect()) {
michael@0:         // the prior test was sufficient
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     // At this point we know all four corners of 'rect' are inside the
michael@0:     // bounds of of this RR. Check to make sure all the corners are inside
michael@0:     // all the curves
michael@0:     return this->checkCornerContainment(rect.fLeft, rect.fTop) &&
michael@0:            this->checkCornerContainment(rect.fRight, rect.fTop) &&
michael@0:            this->checkCornerContainment(rect.fRight, rect.fBottom) &&
michael@0:            this->checkCornerContainment(rect.fLeft, rect.fBottom);
michael@0: }
michael@0: 
michael@0: // There is a simplified version of this method in setRectXY
michael@0: void SkRRect::computeType() const {
michael@0:     SkDEBUGCODE(this->validate();)
michael@0: 
michael@0:     if (fRect.isEmpty()) {
michael@0:         fType = kEmpty_Type;
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     bool allRadiiEqual = true; // are all x radii equal and all y radii?
michael@0:     bool allCornersSquare = 0 == fRadii[0].fX || 0 == fRadii[0].fY;
michael@0: 
michael@0:     for (int i = 1; i < 4; ++i) {
michael@0:         if (0 != fRadii[i].fX && 0 != fRadii[i].fY) {
michael@0:             // if either radius is zero the corner is square so both have to
michael@0:             // be non-zero to have a rounded corner
michael@0:             allCornersSquare = false;
michael@0:         }
michael@0:         if (fRadii[i].fX != fRadii[i-1].fX || fRadii[i].fY != fRadii[i-1].fY) {
michael@0:             allRadiiEqual = false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (allCornersSquare) {
michael@0:         fType = kRect_Type;
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     if (allRadiiEqual) {
michael@0:         if (fRadii[0].fX >= SkScalarHalf(fRect.width()) &&
michael@0:             fRadii[0].fY >= SkScalarHalf(fRect.height())) {
michael@0:             fType = kOval_Type;
michael@0:         } else {
michael@0:             fType = kSimple_Type;
michael@0:         }
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     fType = kComplex_Type;
michael@0: }
michael@0: 
michael@0: static bool matrix_only_scale_and_translate(const SkMatrix& matrix) {
michael@0:     const SkMatrix::TypeMask m = (SkMatrix::TypeMask) (SkMatrix::kAffine_Mask
michael@0:                                     | SkMatrix::kPerspective_Mask);
michael@0:     return (matrix.getType() & m) == 0;
michael@0: }
michael@0: 
michael@0: bool SkRRect::transform(const SkMatrix& matrix, SkRRect* dst) const {
michael@0:     if (NULL == dst) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // Assert that the caller is not trying to do this in place, which
michael@0:     // would violate const-ness. Do not return false though, so that
michael@0:     // if they know what they're doing and want to violate it they can.
michael@0:     SkASSERT(dst != this);
michael@0: 
michael@0:     if (matrix.isIdentity()) {
michael@0:         *dst = *this;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     // If transform supported 90 degree rotations (which it could), we could
michael@0:     // use SkMatrix::rectStaysRect() to check for a valid transformation.
michael@0:     if (!matrix_only_scale_and_translate(matrix)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     SkRect newRect;
michael@0:     if (!matrix.mapRect(&newRect, fRect)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // At this point, this is guaranteed to succeed, so we can modify dst.
michael@0:     dst->fRect = newRect;
michael@0: 
michael@0:     // Now scale each corner
michael@0:     SkScalar xScale = matrix.getScaleX();
michael@0:     const bool flipX = xScale < 0;
michael@0:     if (flipX) {
michael@0:         xScale = -xScale;
michael@0:     }
michael@0:     SkScalar yScale = matrix.getScaleY();
michael@0:     const bool flipY = yScale < 0;
michael@0:     if (flipY) {
michael@0:         yScale = -yScale;
michael@0:     }
michael@0: 
michael@0:     // Scale the radii without respecting the flip.
michael@0:     for (int i = 0; i < 4; ++i) {
michael@0:         dst->fRadii[i].fX = SkScalarMul(fRadii[i].fX, xScale);
michael@0:         dst->fRadii[i].fY = SkScalarMul(fRadii[i].fY, yScale);
michael@0:     }
michael@0: 
michael@0:     // Now swap as necessary.
michael@0:     if (flipX) {
michael@0:         if (flipY) {
michael@0:             // Swap with opposite corners
michael@0:             SkTSwap(dst->fRadii[kUpperLeft_Corner], dst->fRadii[kLowerRight_Corner]);
michael@0:             SkTSwap(dst->fRadii[kUpperRight_Corner], dst->fRadii[kLowerLeft_Corner]);
michael@0:         } else {
michael@0:             // Only swap in x
michael@0:             SkTSwap(dst->fRadii[kUpperRight_Corner], dst->fRadii[kUpperLeft_Corner]);
michael@0:             SkTSwap(dst->fRadii[kLowerRight_Corner], dst->fRadii[kLowerLeft_Corner]);
michael@0:         }
michael@0:     } else if (flipY) {
michael@0:         // Only swap in y
michael@0:         SkTSwap(dst->fRadii[kUpperLeft_Corner], dst->fRadii[kLowerLeft_Corner]);
michael@0:         SkTSwap(dst->fRadii[kUpperRight_Corner], dst->fRadii[kLowerRight_Corner]);
michael@0:     }
michael@0: 
michael@0:     // Since the only transforms that were allowed are scale and translate, the type
michael@0:     // remains unchanged.
michael@0:     dst->fType = fType;
michael@0: 
michael@0:     SkDEBUGCODE(dst->validate();)
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: void SkRRect::inset(SkScalar dx, SkScalar dy, SkRRect* dst) const {
michael@0:     SkRect r = fRect;
michael@0: 
michael@0:     r.inset(dx, dy);
michael@0:     if (r.isEmpty()) {
michael@0:         dst->setEmpty();
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     SkVector radii[4];
michael@0:     memcpy(radii, fRadii, sizeof(radii));
michael@0:     for (int i = 0; i < 4; ++i) {
michael@0:         if (radii[i].fX) {
michael@0:             radii[i].fX -= dx;
michael@0:         }
michael@0:         if (radii[i].fY) {
michael@0:             radii[i].fY -= dy;
michael@0:         }
michael@0:     }
michael@0:     dst->setRectRadii(r, radii);
michael@0: }
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: size_t SkRRect::writeToMemory(void* buffer) const {
michael@0:     SkASSERT(kSizeInMemory == sizeof(SkRect) + sizeof(fRadii));
michael@0: 
michael@0:     memcpy(buffer, &fRect, sizeof(SkRect));
michael@0:     memcpy((char*)buffer + sizeof(SkRect), fRadii, sizeof(fRadii));
michael@0:     return kSizeInMemory;
michael@0: }
michael@0: 
michael@0: size_t SkRRect::readFromMemory(const void* buffer, size_t length) {
michael@0:     if (length < kSizeInMemory) {
michael@0:         return 0;
michael@0:     }
michael@0: 
michael@0:     SkScalar storage[12];
michael@0:     SkASSERT(sizeof(storage) == kSizeInMemory);
michael@0: 
michael@0:     // we make a local copy, to ensure alignment before we cast
michael@0:     memcpy(storage, buffer, kSizeInMemory);
michael@0: 
michael@0:     this->setRectRadii(*(const SkRect*)&storage[0],
michael@0:                        (const SkVector*)&storage[4]);
michael@0:     return kSizeInMemory;
michael@0: }
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: #ifdef SK_DEBUG
michael@0: void SkRRect::validate() const {
michael@0:     bool allRadiiZero = (0 == fRadii[0].fX && 0 == fRadii[0].fY);
michael@0:     bool allCornersSquare = (0 == fRadii[0].fX || 0 == fRadii[0].fY);
michael@0:     bool allRadiiSame = true;
michael@0: 
michael@0:     for (int i = 1; i < 4; ++i) {
michael@0:         if (0 != fRadii[i].fX || 0 != fRadii[i].fY) {
michael@0:             allRadiiZero = false;
michael@0:         }
michael@0: 
michael@0:         if (fRadii[i].fX != fRadii[i-1].fX || fRadii[i].fY != fRadii[i-1].fY) {
michael@0:             allRadiiSame = false;
michael@0:         }
michael@0: 
michael@0:         if (0 != fRadii[i].fX && 0 != fRadii[i].fY) {
michael@0:             allCornersSquare = false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     switch (fType) {
michael@0:         case kEmpty_Type:
michael@0:             SkASSERT(fRect.isEmpty());
michael@0:             SkASSERT(allRadiiZero && allRadiiSame && allCornersSquare);
michael@0: 
michael@0:             SkASSERT(0 == fRect.fLeft && 0 == fRect.fTop &&
michael@0:                      0 == fRect.fRight && 0 == fRect.fBottom);
michael@0:             break;
michael@0:         case kRect_Type:
michael@0:             SkASSERT(!fRect.isEmpty());
michael@0:             SkASSERT(allRadiiZero && allRadiiSame && allCornersSquare);
michael@0:             break;
michael@0:         case kOval_Type:
michael@0:             SkASSERT(!fRect.isEmpty());
michael@0:             SkASSERT(!allRadiiZero && allRadiiSame && !allCornersSquare);
michael@0: 
michael@0:             for (int i = 0; i < 4; ++i) {
michael@0:                 SkASSERT(SkScalarNearlyEqual(fRadii[i].fX, SkScalarHalf(fRect.width())));
michael@0:                 SkASSERT(SkScalarNearlyEqual(fRadii[i].fY, SkScalarHalf(fRect.height())));
michael@0:             }
michael@0:             break;
michael@0:         case kSimple_Type:
michael@0:             SkASSERT(!fRect.isEmpty());
michael@0:             SkASSERT(!allRadiiZero && allRadiiSame && !allCornersSquare);
michael@0:             break;
michael@0:         case kComplex_Type:
michael@0:             SkASSERT(!fRect.isEmpty());
michael@0:             SkASSERT(!allRadiiZero && !allRadiiSame && !allCornersSquare);
michael@0:             break;
michael@0:         case kUnknown_Type:
michael@0:             // no limits on this
michael@0:             break;
michael@0:     }
michael@0: }
michael@0: #endif // SK_DEBUG
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////