I'm looking to save an HBITMAP to a PNG image. Is this possible using only the GDI API? (I'm using C, so no GDI+.) I have only found examples like this, to save to a BMP file. Or should I use libpng and use GetDIBits?
Related question (about reading).
Unfortunately, GDI does not support PNGs.
The Microsoft Windows API does not expose any c++ classes directly from DLLs - The c++ standard does not define an ABI, and as such, the calling conventions and name mangling's used are left to specific implementations to define.
As such, up until Metro at least, all "C++" interfaces supported by the Windows OS have actually been a regular dll exporting a C compatible API, and an accompyining set of c++ header files with the necessary template and inline code.
As such, GDI+ has a Flat API documented in MSDN.
Related
I have been searching to get the source code of the header file <graphics.h> and its associated library in order to integrate it with my C++ program.
At the same time, I am interested in those cross-platform libraries that works on more than one compiler. Just to be more explicit, I am talking about those libraries that are used for drawing shapes, lines, and curves in C++.
<graphics.h> is very old library. It's better to use something that is new
Here are some 2D libraries (platform independent) for C/C++
SDL
GTK+
Qt
Also there is a free very powerful 3D open source graphics library for C++
OGRE
<graphics.h> is not a standard header. Most commonly it refers to the header for Borland's BGI API for DOS and is antiquated at best.
However it is nicely simple; there is a Win32 implementation of the BGI interface called WinBGIm. It is implemented using Win32 GDI calls - the lowest level Windows graphics interface. As it is provided as source code, it is perhaps a simple way of understanding how GDI works.
WinBGIm however is by no means cross-platform. If all you want are simple graphics primitives, most of the higher level GUI libraries such as wxWidgets and Qt support that too. There are simpler libraries suggested in the possible duplicate answers mentioned in the comments.
There is a modern port for this Turbo C graphics interface, it's called WinBGIM, which emulates BGI graphics under MinGW/GCC.
I haven't it tried but it looks promising. For example initgraph creates a window, and
from this point you can draw into that window using the good old functions, at the end closegraph deletes the window. It also has some more advanced extensions (eg. mouse handling and double buffering).
When I first moved from DOS programming to Windows I didn't have internet, and I begged for something simple like this. But at the end I had to learn how to create windows and how to handle events and use device contexts from the offline help of the Windows SDK.
The Borland Graphics Interface, the library fronted by the graphics.h header, has been re-implemented atop SDL. This brings support for modern hardware and operating systems (multiple operating systems, in fact, since SDL is fairly portable).
It can be downloaded here prebuilt for a variety of common desktop targets.
Or if you wish to (or must) build it from source, here is a github mirror.
Note that it is a port of a very old software library and will run atop modern tools, so you should check with the instructor if you intend to use it for class assignments. It would be irritating to fail an assignment because you used idioms that require support from a modern compiler and find that they do not compile on a marking system from the 1980s.
You may find it better to get and develop with a virtual machine clone of the marking system to prevent nasty surprises.
graphics.h appears to something once bundled with Borland and/or Turbo C++, in the 90's.
http://www.daniweb.com/software-development/cpp/threads/17709/88149#post88149
It's unlikely that you will find any support for that file with modern compiler. For other graphics libraries check the list of "related" questions (questions related to this one). E.g., "A Simple, 2d cross-platform graphics library for c or c++?".
Before 2000, I have been using ANSI C for Windows programming. Later I changed to C++ and MFC, then to Delphi, and nowadays I prefer C#, but I'm curious if it is still possible to use plain C to access every API of the modern editions of Windows.
For example, even COM/OLE objects can be dealt with from C.
The Windows APIs list is described here.
Most of the APIs are C-based (structures and functions). However, few are C++ based (classes):
COM+
GDI+
DirectShow
XAudio2
Volume Shadow Copy
Network Diagnostics Framework (NDF) extensible helper
DirectXMath
Compiler is mingw32. Language is C99. OS is windows. Graphics card is Nvidia 260GTX
I can link against opengl32/glu32 and build against it, but nothing from OpenGL 3.x is included... in fact, I would say its probably missing 2.x extensions!
GLEW and GLM are both C++ and doesn't work with straight C. Glee doesn't have any mingw32 binaries (and doesn't build cleanly on my system).
I'm using SDL and that has some OpenGL functions (??), but again, looks way outdated.
I just I don't understand the fundamental problem on why it's so difficult to get C/OpenGL working on windows? Why is is so unique? Why doesn't the Khronos provide an SDK/libraries/headers, etc?
I do OpenGL via Java/lwjgl and takes no time to set it up and get it compiling/running.
In Windows anything above OpenGL-1.1 is only accessible through extensions. This is how it has been designed and how it goes. GLEW works perfectly well with plain C (if I'm not mistaken GLEW is written in plain C).
Khronos cannot provide a SDK because actually providing the OpenGL API is a task left to the operating system vendor and in Windows the graphics drivers are required to provide the implementation. In the case of Windows this is Microsoft, who left the ARB some years ago, in favour of their proprietary Direct3D technology; there used to be heated debates which was the better API, but now that the whole world, except Microsoft settled on OpenGL this time of arguing is over.
Anyway, if you want things to be really easy, instead of GLUT, SDL, etc. use GLFW http://glfw.org, a really excellent OpenGL framework, that does all the hard things for you, does extension loading and OpenGL-3 context setup if you ask it so (you still need some extension wrapper to use extensions in your own code – however creating a pure OpenGL-3 context requires some proxy context, loading a few extensions using that and use the functions obtained to create a real OpenGL-3 context. Just for clarification).
Using C language
Have a look at the Window Imaging Component API. See there.
I have only used it via .NET but the underlying standard Windows lib GDI+ might be what you're after.
Here's the MSDN intro page
I have come across a project where it is required to draw some 2D graphics on a form under Windows and to be able to perform the following tasks:
read image formats jpg, GIF, png, with transparency
monitor mouse and keyboard input to this form
draw simple 2D shapes, eg. line, ellipse, rectangle, pixel set/clear, polygons, ...
draw text with true font types and sizes and measure text sizes for different strings
written in C and can be integrated into Visual Studio 2008 C project
I've tried OpenCV but it lacks the transperency, font types, and GIF decoding and other things
I need your help please, It would be good if the library is easy to learn and use
thanks all
Sounds like a perfect job for SDL
And why not use the GDI built into Windows?
Traditional GDI documentation - http://msdn.microsoft.com/en-us/library/dd145203%28v=VS.85%29.aspx
Newer GDI+ documentation - http://msdn.microsoft.com/en-us/library/ms533798%28VS.85%29.aspx
Some more info added:
I guess I don't understand your requirements. Is cross platform support required? If yes, then use C and some of the cross platform libraries people have mentioned. If this is Windows only, then why not use the APIs that come with Windows?
Since your already using Visual Studio and you want ease of learning and development, why don't you use C# and the.NET libraries? In 2010, that is really the easiest way to build Windows only programs. Windows Forms will likely do everything you need. If you really must write in C and you are Windows only, then use GDI+ (or GDI if you need to support older versions of Windows). If you want to learn classic Windows C programming, go to the source - http://www.charlespetzold.com/pw5/.
As daddz said, you can use SDL for inputs, and image reading. In order to render your 2D primitives, OpenGL will do the work (be sure to create an OpenGL compatible window while calling SDL_CreateWindow). Concerning font rendering, it is not directly implemented in SDL but a couple of libraries can be used (see Survey Of OpenGL Font Technology).