Merge pull request #298 from scratchcpp/sprite_bounding_rect

Add Sprite::boundingRect() method

Author: adazem009

CMakeLists.txt

@@ -50,6 +50,7 @@ target_sources(scratchcpp
     include/scratchcpp/keyevent.h
     include/scratchcpp/iimageformat.h
     include/scratchcpp/iimageformatfactory.h
+    include/scratchcpp/rect.h
 )
 
 add_library(zip SHARED

include/scratchcpp/rect.h

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "global.h"
+#include "spimpl.h"
+
+namespace libscratchcpp
+{
+
+class RectPrivate;
+
+/*! The Rect class represents a rectangle. */
+class LIBSCRATCHCPP_EXPORT Rect
+{
+    public:
+        Rect(double left, double top, double right, double bottom);
+        Rect();
+
+        double left() const;
+        void setLeft(double left);
+
+        double top() const;
+        void setTop(double top);
+
+        double right() const;
+        void setRight(double right);
+
+        double bottom() const;
+        void setBottom(double bottom);
+
+        double width() const;
+        double height() const;
+
+    private:
+        spimpl::impl_ptr<RectPrivate> impl;
+};
+
+} // namespace libscratchcpp

include/scratchcpp/sprite.h

@@ -8,6 +8,7 @@ namespace libscratchcpp
 {
 
 class ISpriteHandler;
+class Rect;
 class SpritePrivate;
 
 /*! \brief The Sprite class represents a Scratch sprite. */
@@ -62,6 +63,8 @@ class LIBSCRATCHCPP_EXPORT Sprite : public Target
         void setRotationStyle(const std::string &newRotationStyle);
         void setRotationStyle(const char *newRotationStyle);
 
+        Rect boundingRect() const;
+
     private:
         Target *dataSource() const override;
 

src/CMakeLists.txt

@@ -6,6 +6,9 @@ target_sources(scratchcpp
     scratchconfiguration.cpp
     scratchconfiguration_p.cpp
     scratchconfiguration_p.h
+    rect.cpp
+    rect_p.cpp
+    rect_p.h
 )
 
 add_subdirectory(blocks)

src/rect.cpp

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include <scratchcpp/rect.h>
+#include <cmath>
+#include "rect_p.h"
+
+using namespace libscratchcpp;
+
+/*! Constructs Rect. */
+Rect::Rect(double left, double top, double right, double bottom) :
+    impl(spimpl::make_impl<RectPrivate>(left, top, right, bottom))
+{
+}
+
+/*! \copydoc Rect() */
+Rect::Rect() :
+    impl(spimpl::make_impl<RectPrivate>())
+{
+}
+
+/*! Returns the x-coordinate of the left edge. */
+double Rect::left() const
+{
+    return impl->left;
+}
+
+/*! Sets the x-coordinate of the left edge. */
+void Rect::setLeft(double left)
+{
+    impl->left = left;
+}
+
+/*! Returns the y-coordinate of the top edge. */
+double Rect::top() const
+{
+    return impl->top;
+}
+
+/*! Sets the y-coordinate of the top edge. */
+void Rect::setTop(double top)
+{
+    impl->top = top;
+}
+
+/*! Returns the x-coordinate of the right edge. */
+double Rect::right() const
+{
+    return impl->right;
+}
+
+/*! Sets the x-coordinate of the right edge. */
+void Rect::setRight(double right)
+{
+    impl->right = right;
+}
+
+/*! Returns the y-coordinate of the bottom edge. */
+double Rect::bottom() const
+{
+    return impl->bottom;
+}
+
+/*! Sets the y-coordinate of the bottom edge. */
+void Rect::setBottom(double bottom)
+{
+    impl->bottom = bottom;
+}
+
+/*! Returns the width of the rectangle. */
+double Rect::width() const
+{
+    return std::abs(impl->right - impl->left);
+}
+
+/*! Returns the height of the rectangle. */
+double Rect::height() const
+{
+    return std::abs(impl->top - impl->bottom);
+}

src/rect_p.cpp

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include "rect_p.h"
+
+namespace libscratchcpp
+{
+
+RectPrivate::RectPrivate(double left, double top, double right, double bottom) :
+    left(left),
+    top(top),
+    right(right),
+    bottom(bottom)
+{
+}
+
+RectPrivate::RectPrivate()
+{
+}
+
+} // namespace libscratchcpp

src/rect_p.h

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+namespace libscratchcpp
+{
+
+struct RectPrivate
+{
+        RectPrivate(double left, double top, double right, double bottom);
+        RectPrivate();
+
+        double left = 0;
+        double top = 0;
+        double right = 0;
+        double bottom = 0;
+};
+
+} // namespace libscratchcpp

src/scratch/sprite.cpp

@@ -6,6 +6,7 @@
 #include <scratchcpp/variable.h>
 #include <scratchcpp/list.h>
 #include <scratchcpp/costume.h>
+#include <scratchcpp/rect.h>
 #include <cassert>
 
 #include "sprite_p.h"
@@ -15,7 +16,7 @@ using namespace libscratchcpp;
 /*! Constructs Sprite. */
 Sprite::Sprite() :
     Target(),
-    impl(spimpl::make_unique_impl<SpritePrivate>())
+    impl(spimpl::make_unique_impl<SpritePrivate>(this))
 {
 }
 
@@ -297,6 +298,15 @@ void Sprite::setRotationStyle(const char *newRotationStyle)
     setRotationStyle(std::string(newRotationStyle));
 }
 
+/*! Returns the bounding rectangle of the sprite. */
+Rect Sprite::boundingRect() const
+{
+    Rect ret;
+    impl->getBoundingRect(&ret);
+
+    return ret;
+}
+
 Target *Sprite::dataSource() const
 {
     return impl->cloneRoot;

src/scratch/sprite_p.cpp

@@ -1,12 +1,18 @@
 // SPDX-License-Identifier: Apache-2.0
 
 #include <scratchcpp/ispritehandler.h>
+#include <scratchcpp/rect.h>
+#include <scratchcpp/costume.h>
+#include <cmath>
 
 #include "sprite_p.h"
 
 using namespace libscratchcpp;
 
-SpritePrivate::SpritePrivate()
+static const double pi = std::acos(-1); // TODO: Use std::numbers::pi in C++20
+
+SpritePrivate::SpritePrivate(Sprite *sprite) :
+    sprite(sprite)
 {
 }
 
@@ -28,3 +34,59 @@ void SpritePrivate::setCostumeData(const char *data)
     if (iface)
         iface->onCostumeChanged(data);
 }
+
+void SpritePrivate::getBoundingRect(Rect *out) const
+{
+    assert(out);
+    assert(sprite);
+    // TODO: Make currentCostume() return the costume
+    auto costume = sprite->costumeAt(sprite->currentCostume() - 1);
+
+    if (!costume) {
+        out->setLeft(0);
+        out->setTop(0);
+        out->setRight(0);
+        out->setBottom(0);
+        return;
+    }
+
+    double cosTheta = std::cos((90 - direction) * pi / 180);
+    double sinTheta = std::sin((90 - direction) * pi / 180);
+    double maxX = 0, maxY = 0, minX = 0, minY = 0;
+    bool firstPixel = true;
+    unsigned int width = costume->width();
+    unsigned int height = costume->height();
+    double rotationCenterX = width / 2.0 + costume->rotationCenterX();
+    double rotationCenterY = height / 2.0 + costume->rotationCenterY();
+    Rgb **bitmap = costume->bitmap();
+
+    for (unsigned int y = 0; y < height; y++) {
+        for (unsigned int x = 0; x < width; x++) {
+            if (bitmap[y][x] != rgba(0, 0, 0, 0)) {
+                double rotatedX = ((x - rotationCenterX) * cosTheta - (y - rotationCenterY) * sinTheta);
+                double rotatedY = ((x - rotationCenterX) * sinTheta + (y - rotationCenterY) * cosTheta);
+
+                if (firstPixel) {
+                    firstPixel = false;
+                    minX = maxX = rotatedX;
+                    minY = maxY = rotatedY;
+                } else {
+                    if (rotatedX < minX)
+                        minX = rotatedX;
+                    else if (rotatedX > maxX)
+                        maxX = rotatedX;
+
+                    if (rotatedY < minY)
+                        minY = rotatedY;
+                    else if (rotatedY > maxY)
+                        maxY = rotatedY;
+                }
+            }
+        }
+    }
+
+    out->setLeft(x + minX);
+    out->setTop(y + maxY);
+    out->setRight(x + maxX);
+    out->setBottom(y + minY);
+}

src/scratch/sprite_p.h

@@ -7,15 +7,19 @@
 namespace libscratchcpp
 {
 
+class Rect;
+
 struct SpritePrivate
 {
-        SpritePrivate();
+        SpritePrivate(Sprite *sprite);
         SpritePrivate(const SpritePrivate &) = delete;
 
         void removeClone(Sprite *clone);
 
         void setCostumeData(const char *data);
+        void getBoundingRect(Rect *out) const;
 
+        Sprite *sprite = nullptr;
         ISpriteHandler *iface = nullptr;
         Sprite *cloneRoot = nullptr;
         Sprite *cloneParent = nullptr;