Merge pull request #292 from scratchcpp/png

Add PNG image format

Author: adazem009

docs/Image formats.md

@@ -1,7 +1,7 @@
 \page imageFormats Image formats
 
 To work with costumes, libscratchcpp has to read image files from Scratch projects.
-Only JPEG is currently supported, but support for PNG is coming soon.
+Only JPEG and PNG are currently supported, but SVG is going to be supported in the future.
 
 # Implementing a custom image format
 To implement a custom image format that libscratchcpp doesn't support,

src/imageformats/CMakeLists.txt

@@ -1,4 +1,5 @@
 option(LIBSCRATCHCPP_JPEG_SUPPORT "JPEG image support" ON)
+option(LIBSCRATCHCPP_PNG_SUPPORT "PNG image support" ON)
 
 add_subdirectory(stub)
 
@@ -7,6 +8,11 @@ if (LIBSCRATCHCPP_JPEG_SUPPORT)
  add_subdirectory(jpeg)
 endif()
 
+if (LIBSCRATCHCPP_PNG_SUPPORT)
+ target_compile_definitions(scratchcpp PRIVATE PNG_SUPPORT)
+ add_subdirectory(png)
+endif()
+
 target_sources(scratchcpp
  PRIVATE
  defaultimageformats.cpp

src/imageformats/defaultimageformats.cpp

@@ -7,6 +7,10 @@
 #include "jpeg/jpegimageformatfactory.h"
 #endif
 
+#ifdef PNG_SUPPORT
+#include "png/pngimageformatfactory.h"
+#endif
+
 namespace libscratchcpp
 {
 
@@ -18,6 +22,10 @@ class DefaultImageFormats
 #ifdef JPEG_SUPPORT
  ScratchConfiguration::registerImageFormat("jpg", std::make_shared<JpegImageFormatFactory>());
 #endif
+
+#ifdef PNG_SUPPORT
+ ScratchConfiguration::registerImageFormat("png", std::make_shared<PngImageFormatFactory>());
+#endif
  }
 };
 

src/imageformats/png/CMakeLists.txt

@@ -0,0 +1,9 @@
+target_sources(scratchcpp
+ PRIVATE
+ pngimageformat.cpp
+ pngimageformat.h
+ pngimageformatfactory.cpp
+ pngimageformatfactory.h
+)
+
+target_link_libraries(scratchcpp PRIVATE gd)

src/imageformats/png/pngimageformat.cpp

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include "pngimageformat.h"
+
+using namespace libscratchcpp;
+
+PngImageFormat::PngImageFormat()
+{
+}
+
+PngImageFormat::~PngImageFormat()
+{
+ if (m_img)
+ gdImageDestroy(m_img);
+}
+
+void PngImageFormat::setData(unsigned int size, void *data)
+{
+ if (m_img)
+ gdImageDestroy(m_img);
+
+ m_img = gdImageCreateFromPngPtr(size, data);
+}
+
+unsigned int PngImageFormat::width() const
+{
+ return m_img ? gdImageSX(m_img) : 0;
+}
+
+unsigned int PngImageFormat::height() const
+{
+ return m_img ? gdImageSY(m_img) : 0;
+}
+
+Rgb PngImageFormat::colorAt(unsigned int x, unsigned int y, double scale) const
+{
+ if (!m_img)
+ return 0;
+
+ int color = gdImageGetPixel(m_img, x / scale, y / scale);
+ int alpha = 127 - gdImageAlpha(m_img, color); // gdImageAlpha() returns values from 0 to 127
+
+ if (alpha == 127) // 127 should be the max (255)
+ alpha = 255;
+ else
+ alpha *= 2;
+
+ return rgba(gdImageRed(m_img, color), gdImageGreen(m_img, color), gdImageBlue(m_img, color), alpha);
+}

src/imageformats/png/pngimageformat.h

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <scratchcpp/iimageformat.h>
+#include <gd.h>
+
+namespace libscratchcpp
+{
+
+class PngImageFormat : public IImageFormat
+{
+ public:
+ PngImageFormat();
+ ~PngImageFormat();
+
+ void setData(unsigned int size, void *data) override;
+
+ unsigned int width() const override;
+ unsigned int height() const override;
+
+ Rgb colorAt(unsigned int x, unsigned int y, double scale) const override;
+
+ private:
+ gdImagePtr m_img = nullptr;
+};
+
+} // namespace libscratchcpp

src/imageformats/png/pngimageformatfactory.cpp

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#include "pngimageformatfactory.h"
+#include "pngimageformat.h"
+
+using namespace libscratchcpp;
+
+PngImageFormatFactory::PngImageFormatFactory()
+{
+}
+
+std::shared_ptr<IImageFormat> PngImageFormatFactory::createInstance() const
+{
+ return std::make_shared<PngImageFormat>();
+}

src/imageformats/png/pngimageformatfactory.h

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <scratchcpp/iimageformatfactory.h>
+
+namespace libscratchcpp
+{
+
+class PngImageFormatFactory : public IImageFormatFactory
+{
+ public:
+ PngImageFormatFactory();
+
+ std::shared_ptr<IImageFormat> createInstance() const override;
+};
+
+} // namespace libscratchcpp