From e2c40b8d6cabc68eda634e103d0824fb58d5908b Mon Sep 17 00:00:00 2001 From: Tavian Barnes Date: Mon, 6 Jul 2009 16:36:47 +0000 Subject: Change C++ canvas import/export semantics. --- libdimensionxx/canvas.cpp | 24 +++--- libdimensionxx/dimensionxx/canvas.hpp | 20 ++--- libdimensionxx/dimensionxx/png.hpp | 60 ++++++-------- libdimensionxx/png.cpp | 143 ++++++++++++++-------------------- 4 files changed, 103 insertions(+), 144 deletions(-) (limited to 'libdimensionxx') diff --git a/libdimensionxx/canvas.cpp b/libdimensionxx/canvas.cpp index c8b3389..3ff9d32 100644 --- a/libdimensionxx/canvas.cpp +++ b/libdimensionxx/canvas.cpp @@ -24,61 +24,59 @@ namespace Dimension { // Allocate the canvas with dmnsn_new_canvas() Canvas::Canvas(unsigned int width, unsigned int height) - : m_canvas(dmnsn_new_canvas(width, height)) { } + : m_canvas(new dmnsn_canvas*(dmnsn_new_canvas(width, height))) { } // Wrap an existing dmnsn_canvas* Canvas::Canvas(dmnsn_canvas* canvas) - : m_canvas(canvas) { } + : m_canvas(new dmnsn_canvas*(canvas)) { } // Virtual destructor: delete the canvas with dmnsn_delete_canvas(). Canvas::~Canvas() { - dmnsn_delete_canvas(m_canvas); + if (m_canvas && m_canvas.unique()) { + dmnsn_delete_canvas(dmnsn()); + } } // Get the width unsigned int Canvas::width() const { - return m_canvas->x; + return dmnsn()->x; } // Get the height unsigned int Canvas::height() const { - return m_canvas->y; + return dmnsn()->y; } // Get a particular pixel Color Canvas::pixel(unsigned int x, unsigned int y) const { - return Color(dmnsn_get_pixel(m_canvas, x, y)); + return Color(dmnsn_get_pixel(dmnsn(), x, y)); } // Set a particular pixel void Canvas::pixel(unsigned int x, unsigned int y, const Color& c) { - dmnsn_set_pixel(m_canvas, x, y, c.dmnsn()); + dmnsn_set_pixel(dmnsn(), x, y, c.dmnsn()); } // Return the wrapped canvas dmnsn_canvas* Canvas::dmnsn() { - return m_canvas; + return *m_canvas; } // Return a const version of the wrapped canvas const dmnsn_canvas* Canvas::dmnsn() const { - return m_canvas; + return *m_canvas; } - - // Protected default constructor: set m_canvas to NULL. - Canvas::Canvas() - : m_canvas(0) { } } diff --git a/libdimensionxx/dimensionxx/canvas.hpp b/libdimensionxx/dimensionxx/canvas.hpp index f519fbd..b8f2887 100644 --- a/libdimensionxx/dimensionxx/canvas.hpp +++ b/libdimensionxx/dimensionxx/canvas.hpp @@ -23,6 +23,8 @@ #ifndef DIMENSIONXX_CANVAS_HPP #define DIMENSIONXX_CANVAS_HPP +#include + namespace Dimension { // Base canvas class. Wraps a dmnsn_canvas*. @@ -31,10 +33,14 @@ namespace Dimension public: // Allocate a dmnsn_canvas of specified width and height Canvas(unsigned int width, unsigned int height); + // Wrap an existing canvas explicit Canvas(dmnsn_canvas* canvas); + + // Canvas(const Canvas& canvas); + // Delete the canvas - virtual ~Canvas(); + ~Canvas(); // Get the width and height unsigned int width() const; @@ -48,17 +54,11 @@ namespace Dimension dmnsn_canvas* dmnsn(); const dmnsn_canvas* dmnsn() const; - protected: - // Derived classes may want to set m_canvas later. Set it to NULL now, so - // that the destructor can still dmnsn_delete_canvas it. - Canvas(); - - dmnsn_canvas* m_canvas; - private: - // Copying prohibited - Canvas(const Canvas&); + // Copy-assignment prohibited Canvas& operator=(const Canvas&); + + std::tr1::shared_ptr m_canvas; }; } diff --git a/libdimensionxx/dimensionxx/png.hpp b/libdimensionxx/dimensionxx/png.hpp index 980840c..17cb883 100644 --- a/libdimensionxx/dimensionxx/png.hpp +++ b/libdimensionxx/dimensionxx/png.hpp @@ -28,55 +28,43 @@ namespace Dimension { - // PNG_Canvas handles reading a Canvas from a PNG file, writing one to a PNG - // file, or both, depending on what type of stream(s) are given to the - // constructor. - class PNG_Canvas : public Canvas + class PNG_Writer { public: - // Input PNG_Canvas; read the Canvas from istr now - explicit PNG_Canvas(std::istream& istr); + PNG_Writer(Canvas& canvas, std::ostream& ostr); + ~PNG_Writer(); - // Output PNG_Canvas; write the Canvas to ostr at destruction, or when - // write() is called. - PNG_Canvas(unsigned int x, unsigned int y, std::ostream& ostr); - - // I/O PNG_Canvas; read the Canvas from istr now, and write to ostr at - // destruction or then write() is called. - PNG_Canvas(std::istream& istr, std::ostream& ostr); + void write(); + Progress write_async(); - // Call write() if we're an output PNG_Canvas, but trap any exceptions and - // report a dmnsn_error() instead. - virtual ~PNG_Canvas(); + private: + // Copying prohibited + PNG_Writer(const PNG_Writer&); + PNG_Writer& operator=(const PNG_Writer&); - // Write the Canvas to the output stream, throwing a Dimension_Error on - // error. - void write(); + Canvas* m_canvas; + std::ostream* m_ostr; + bool m_written; + }; - // Write the Canvas to the output stream in the background - Progress write_async(); + class PNG_Reader + { + public: + PNG_Reader(std::istream& istr); + // ~PNG_Reader(); - // Construct an input or I/O PNG_Canvas in the background - static Progress read_async(std::istream& istr); - explicit PNG_Canvas(Progress& progress); - explicit PNG_Canvas(Progress& progress, std::ostream& ostr); + Canvas read(); - protected: - // In case a derived class needs to set m_canvas after we're constructed - explicit PNG_Canvas(std::ostream& ostr); + Progress read_async(); + static Canvas finish(Progress& progress); private: // Copying prohibited - PNG_Canvas(const PNG_Canvas&); - PNG_Canvas& operator=(const PNG_Canvas&); + PNG_Reader(const PNG_Reader&); + PNG_Reader& operator=(const PNG_Reader&); std::istream* m_istr; - std::ostream* m_ostr; - bool m_written; - - // Read the Canvas from a PNG file, and throw a Dimension_Error upon - // failure. - void read(); + bool m_read; }; } diff --git a/libdimensionxx/png.cpp b/libdimensionxx/png.cpp index b626269..1f61e72 100644 --- a/libdimensionxx/png.cpp +++ b/libdimensionxx/png.cpp @@ -23,57 +23,42 @@ namespace Dimension { - PNG_Canvas::PNG_Canvas(std::istream& istr) - : Canvas(), m_istr(&istr), m_ostr(0), m_written(false) + PNG_Writer::PNG_Writer(Canvas& canvas, std::ostream& ostr) + : m_canvas(&canvas), m_ostr(&ostr), m_written(false) { - read(); + // Optimize the canvas for PNG export + dmnsn_png_optimize_canvas(m_canvas->dmnsn()); } - PNG_Canvas::PNG_Canvas(unsigned int x, unsigned int y, std::ostream& ostr) - : Canvas(x, y), m_istr(0), m_ostr(&ostr), m_written(false) - { } - - PNG_Canvas::PNG_Canvas(std::istream& istr, std::ostream& ostr) - : Canvas(), m_istr(&istr), m_ostr(&ostr), m_written(false) - { - read(); - } - - // PNG_Canvas destructor. Call write() to write the PNG file if not already + // PNG_Writer destructor. Call write() to write the PNG file if not already // written, but catch any exceptions and instead report the error with // dmnsn_error() to avoid throwing from a destructor. - PNG_Canvas::~PNG_Canvas() + PNG_Writer::~PNG_Writer() { - if (m_ostr && !m_written) { + if (!m_written) { try { write(); } catch (...) { dmnsn_error(SEVERITY_MEDIUM, - "Writing canvas to PNG failed in PNG_Canvas destructor."); + "Writing canvas to PNG failed in PNG_Writer destructor."); } } } // Write the PNG file. Uses the FILE_Cookie() interface to make a FILE* // corresponding to an std::ostream (including std::ostringstream, etc). - void PNG_Canvas::write() + void PNG_Writer::write() { if (m_written) { // Does writing a PNG file twice make sense? throw Dimension_Error("Attempt to write canvas to PNG twice."); } - if (!m_ostr) { - // Don't call write() if we're not an output PNG_Canvas... - throw Dimension_Error("Attempt to write canvas to PNG without an output" - " stream."); - } - // Make the C++/C I/O interface FILE_Cookie cookie(*m_ostr); // Write the PNG file - if (dmnsn_png_write_canvas(m_canvas, cookie.file())) { + if (dmnsn_png_write_canvas(m_canvas->dmnsn(), cookie.file())) { // The actual write operation failed, for some reason throw Dimension_Error("Writing canvas to PNG failed."); } @@ -83,19 +68,13 @@ namespace Dimension // Write a PNG file in the background Progress - PNG_Canvas::write_async() + PNG_Writer::write_async() { if (m_written) { // Does writing a PNG file twice make sense? throw Dimension_Error("Attempt to write canvas to PNG twice."); } - if (!m_ostr) { - // Don't call write_async() if we're not an output PNG_Canvas... - throw Dimension_Error("Attempt to write canvas to PNG without an output" - " stream."); - } - m_written = true; // We've written the file now, don't do it again // Object to persist local variables past function return @@ -107,7 +86,7 @@ namespace Dimension // Start the asynchronous task dmnsn_progress *progress - = dmnsn_png_write_canvas_async(m_canvas, cookie->file()); + = dmnsn_png_write_canvas_async(m_canvas->dmnsn(), cookie->file()); if (!progress) { throw Dimension_Error("Starting background PNG write failed."); } @@ -116,20 +95,58 @@ namespace Dimension return Progress(progress, persister); } + // Construct a PNG reader + PNG_Reader::PNG_Reader(std::istream& istr) + : m_istr(&istr), m_read(false) { } + + // Read a canvas from a PNG file. Uses the FILE_Cookie() interface to make a + // FILE* corresponding to an std::istream + Canvas + PNG_Reader::read() + { + if (m_read) { + // Does reading a PNG file twice make sense? + throw Dimension_Error("Attempt to read canvas from PNG twice."); + } + + // Make the C++/C I/O interface + FILE_Cookie cookie(*m_istr); + + // Read the canvas from a PNG file + dmnsn_canvas* canvas = dmnsn_png_read_canvas(cookie.file()); + if (!canvas) { + // The read operation failed + throw Dimension_Error("Reading canvas from PNG failed."); + } + + // Only set m_read if nothing threw an exception + Canvas ret(canvas); + m_read = true; + return ret; + } + // Read a PNG file in the background Progress - PNG_Canvas::read_async(std::istream& istr) + PNG_Reader::read_async() { + if (m_read) { + // Does reading a PNG file twice make sense? + throw Dimension_Error("Attempt to read canvas from PNG twice."); + } + + // Don't read again + m_read = true; + // Object to persist local variables past function return Persister persister; // Store a pointer to a dmnsn_canvas* in the persister to later construct - // the PNG_Canvas + // the PNG_Writer dmnsn_canvas** canvas = new dmnsn_canvas*; persister.persist(canvas); // Make the C++/C I/O interface - FILE_Cookie* cookie = new FILE_Cookie(istr); + FILE_Cookie* cookie = new FILE_Cookie(*m_istr); persister.persist(cookie); // Start the asynchronous task @@ -143,11 +160,11 @@ namespace Dimension return Progress(progress, persister); } - // Construct an input PNG_Canvas from a background task - PNG_Canvas::PNG_Canvas(Progress& progress) - : Canvas(), m_istr(0), m_ostr(0), m_written(false) + // Construct an input PNG_Writer from a background task + Canvas + PNG_Reader::finish(Progress& progress) { - // Will throw if progress is not from a PNG_Canvas::read_async call + // Will throw if progress is not from a PNG_Writer::read_async call dmnsn_canvas** canvas = progress.persister().first().persisted(); @@ -158,50 +175,6 @@ namespace Dimension throw; } - m_canvas = *canvas; - } - - // Construct an I/O PNG_Canvas from a background task - PNG_Canvas::PNG_Canvas(Progress& progress, std::ostream& ostr) - : Canvas(), m_istr(0), m_ostr(&ostr), m_written(false) - { - // Will throw if progress is not from a PNG_Canvas::read_async call - dmnsn_canvas** canvas - = progress.persister().first().persisted(); - - try { - progress.finish(); - } catch (...) { - dmnsn_delete_canvas(*canvas); - throw; - } - - m_canvas = *canvas; - } - - // Protected constructor which sets the canvas to NULL for now - PNG_Canvas::PNG_Canvas(std::ostream& ostr) - : Canvas(), m_istr(0), m_ostr(&ostr), m_written(false) - { } - - // Read a canvas from a PNG file. Uses the FILE_Cookie() interface to make a - // FILE* corresponding to an std::istream (including std::istringstream, etc). - void PNG_Canvas::read() - { - if (!m_istr) { - // read() is private, and only called from the appropriate constructors, - // so this REALLY shouldn't happen. - throw Dimension_Error("Attempt to read canvas from PNG without an input" - " stream."); - } - - // Make the C++/C I/O interface - FILE_Cookie cookie(*m_istr); - - // Read the canvas from a PNG file - if (!(m_canvas = dmnsn_png_read_canvas(cookie.file()))) { - // The read operation failed - throw Dimension_Error("Reading canvas from PNG failed."); - } + return Canvas(*canvas); } } -- cgit v1.2.3