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E V A S - 0.5.0 ------------------------------------------------------------------------------- This is the ``E Canvas'' - a rip off of some of the other canvas's floating about - Tk and gnome too. it's at the Xlib level. it's intended to be accelerated by hardware or highly optimised software where possible. It is intended to be simple and allow for the building of interfaces ontop of it. What you NEED: * Imlib2 1.0.3 or higher (and development headers) * Freetype 1.1, 1.2 or 1.3 - NOT 2.0 and development headers * X11R6 and development headersand libraries If you want hardware acceleration to be available: * OpenGL 1.0 and headers, with hardware accel support and an Xserver with that too - your milage will vary (Xfree86 4.0 with DRI or Nvidia drivers for example). make sure you dont have mutliepl libGL's and multiple GL headers on your system. Rememebr most GL drivers are buggy and you will experience problems. See your driver maintainers for these :) if you got this from cvs do: ./autogen.sh otherwise do: ./configure then to compile: make if you wish to install (as root): make install in the test directory you will find a test program: cd test ./evas_test This is an overall demo of what Evas can do. You can select the rendering mode on the left by simply clicking it. Just sit back, watch and relax. There is also ./evas_test_old this will by default try the software engine - if you don't have a fast cpu it will be slow. You can try the other engines: ./evas_test_old -m x11 ./evas_test_old -m soft -s 0 ./evas_test_old -m hard x11 is the X11 pixmap engine. -s 0 turns off ``dithering'' and smooth shading for image objects here for better speed. hard is the opengl hardware 3D engine. Note that if you do NOT have real hardware accelerated GL it will be SLOOOOOOOOOOOOOW - VERY slow. Much slower than software. Also Mesa 3.2 and below has known bugs that cause a segv. It's been fixed in Mesa 3.3. If evas didn't find OpenGL it will have built a software only engine so you don't need to try hardware since this will fall back to software mode automatically. There is a new evas_test program being written too - it's in progress, so wait for it to be complete. ------------------------------------------------------------------------------- MORE DETAILED DESCRIPTION: ------------------------------------------------------------------------------- Evas? Canvas? What? OK.. you're baffled as to what that stuff is. Time to explain. A canvas is a high-level rendering engine. Instead of a program having to handle exposes or updates then redraw bit by bit (draw line, draw box, paste image etc.) after having figured out what has changed and what need to be re-rendered - what data loaded in maps to what... then finally order the draw in the right way to optimize it - a canvas provides a high-level API to this kind of thing and handles all the smarts inside. The result is an application creates an Evas & attaches that evas to a window. Now it just creates objects - create an image object, a text object, a line object, a rectangle object etc. It just moves and resizes these objects around by calling routines in Evas - Evas handles redrawing, scaling, ordering the draws to account for layers, clipping objects out that don't exist in the visible Evas area etc. All the application need do is call evas_redraw when it becomes idle to have the evas redraw what has changed. This means less headache for the application programmer. Now why do this as a whole new library? Well - because the library can render the Evas as fast as possible. It uses Imlib2 to do the grunt work of loading images - and beyond that it can currently use either imlib2, OpenGL or X11 to render to the Evas - if you have decent hardware that's supported by OpenGL you will see in the area of 10-50 times (in future even higher) speedups in rendering using the GL backend instead of the Imlib2 one (even though Imlib2 is a highly optimized software rendering engine). The good thing here is that the application can choose what system to use. If that system isn't available or Evas didn't compile with it, it will fall back to the nearest approximation (it will ALWAYS have Imlib2 and X11 rendering backends - Imlib2 being able to actually alpha blend, but X11 keeping the rendering server-side with pixmaps and clip masks) so this means a highly optimized rendering subsystem to build more complex things ontop of. As it stands right now the API is still under construction - don't bank on it remaining 100% stable. The backend of evas currently seems to have no bugs or leaks that I know of, so feel free to punish it. |