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To: sdl@libsdl.org From: Christian Walther <cwalther@gmx.ch> Date: Thu, 15 Dec 2005 21:19:53 +0100 Subject: [SDL] More mouse enhancements for Mac OS X The attached patch brings two more enhancements to mouse handling on Mac OS X (Quartz): 1. Currently, after launching an SDL application, SDL's notion of the mouse position is stuck in the top left corner (0,0) until the first time the mouse is moved. That's because the UpdateMouse() function isn't implemented in the Quartz driver. This patch adds it. 2. When grabbing input while the mouse cursor is hidden, the function CGAssociateMouseAndMouseCursorPosition(0) is called, which prevents the system's notion of the mouse location from moving (and therefore leaving the SDL window) even when the mouse is moved. However, apparently the Wacom tablet driver (and maybe other special pointing device drivers) doesn't care about that setting and still allows the mouse location to go outside of the window. Interestingly, the system cursor, which is made visible by the existing code in SDL in that case, does not follow the mouse location, but appears in the middle of the SDL window. The mouse location being outside of the window however means that mouse button events go to background applications (or the dock or whatever is there), which is very confusing to the user who sees no cursor outside of the SDL window. I have not found any way of intercepting these events (and that's probably by design, as "normal" applications shouldn't prevent the user from bringing other applications' windows to the front by clicking on them). An idea would be placing a fully transparent, screen-filling window in front of everything, but I fear that this might affect rendering performance (by doing unnecessary compositing, using up memory, or whatever). The deluxe solution to the problem would be talking to the tablet driver using AppleEvents to tell it to constrain its mapped area to the window (see Wacom's "TabletEventDemo" sample app, http://www.wacomeng.com/devsupport/mac/downloads.html), but I think that the bloat that solution would add to SDL would outweigh its usefulness. What I did instead in my patch is reassociating mouse and cursor when the mouse leaves the window while an invisible grab is in effect, and restoring the grab when the window is entered. That way, the grab can still be effectively broken by a tablet, but at least it's obvious to the user that it is broken. That change is minimal - it doesn't affect operation with a mouse (or a trackpad), and the code that it adds is not executed on every PumpEvents() call, only when entering and leaving the window. Unless there are any concerns about the patch, please apply. Feel free to shorten the lengthy comment in SDL_QuartzEvents.m if you think it's too verbose. Thanks -Christian
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 02 Jan 2006 00:31:00 +0000
parents 355632dca928
children
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<HTML
><HEAD
><TITLE
>Video</TITLE
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><DIV
CLASS="CHAPTER"
><H1
><A
NAME="VIDEO"
></A
>Chapter 6. Video</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="sdlgetvideosurface.html"
>SDL_GetVideoSurface</A
>&nbsp;--&nbsp;returns a pointer to the current display surface</DT
><DT
><A
HREF="sdlgetvideoinfo.html"
>SDL_GetVideoInfo</A
>&nbsp;--&nbsp;returns a pointer to information about the video hardware</DT
><DT
><A
HREF="sdlvideodrivername.html"
>SDL_VideoDriverName</A
>&nbsp;--&nbsp;Obtain the name of the video driver</DT
><DT
><A
HREF="sdllistmodes.html"
>SDL_ListModes</A
>&nbsp;--&nbsp;Returns a pointer to an array of available screen dimensions for 
the given format and video flags</DT
><DT
><A
HREF="sdlvideomodeok.html"
>SDL_VideoModeOK</A
>&nbsp;--&nbsp;Check to see if a particular video mode is supported.</DT
><DT
><A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>&nbsp;--&nbsp;Set up a video mode with the specified width, height and bits-per-pixel.</DT
><DT
><A
HREF="sdlupdaterect.html"
>SDL_UpdateRect</A
>&nbsp;--&nbsp;Makes sure the given area is updated on the given screen.</DT
><DT
><A
HREF="sdlupdaterects.html"
>SDL_UpdateRects</A
>&nbsp;--&nbsp;Makes sure the given list of rectangles is updated on the given screen.</DT
><DT
><A
HREF="sdlflip.html"
>SDL_Flip</A
>&nbsp;--&nbsp;Swaps screen buffers</DT
><DT
><A
HREF="sdlsetcolors.html"
>SDL_SetColors</A
>&nbsp;--&nbsp;Sets a portion of the colormap for the given 8-bit surface.</DT
><DT
><A
HREF="sdlsetpalette.html"
>SDL_SetPalette</A
>&nbsp;--&nbsp;Sets the colors in the palette of an 8-bit surface.</DT
><DT
><A
HREF="sdlsetgamma.html"
>SDL_SetGamma</A
>&nbsp;--&nbsp;Sets the color gamma function for the display</DT
><DT
><A
HREF="sdlgetgammaramp.html"
>SDL_GetGammaRamp</A
>&nbsp;--&nbsp;Gets the color gamma lookup tables for the display</DT
><DT
><A
HREF="sdlsetgammaramp.html"
>SDL_SetGammaRamp</A
>&nbsp;--&nbsp;Sets the color gamma lookup tables for the display</DT
><DT
><A
HREF="sdlmaprgb.html"
>SDL_MapRGB</A
>&nbsp;--&nbsp;Map a RGB color value to a pixel format.</DT
><DT
><A
HREF="sdlmaprgba.html"
>SDL_MapRGBA</A
>&nbsp;--&nbsp;Map a RGBA color value to a pixel format.</DT
><DT
><A
HREF="sdlgetrgb.html"
>SDL_GetRGB</A
>&nbsp;--&nbsp;Get RGB values from a pixel in the specified pixel format.</DT
><DT
><A
HREF="sdlgetrgba.html"
>SDL_GetRGBA</A
>&nbsp;--&nbsp;Get RGBA values from a pixel in the specified pixel format.</DT
><DT
><A
HREF="sdlcreatergbsurface.html"
>SDL_CreateRGBSurface</A
>&nbsp;--&nbsp;Create an empty SDL_Surface</DT
><DT
><A
HREF="sdlcreatergbsurfacefrom.html"
>SDL_CreateRGBSurfaceFrom</A
>&nbsp;--&nbsp;Create an SDL_Surface from pixel data</DT
><DT
><A
HREF="sdlfreesurface.html"
>SDL_FreeSurface</A
>&nbsp;--&nbsp;Frees (deletes) a SDL_Surface</DT
><DT
><A
HREF="sdllocksurface.html"
>SDL_LockSurface</A
>&nbsp;--&nbsp;Lock a surface for directly access.</DT
><DT
><A
HREF="sdlunlocksurface.html"
>SDL_UnlockSurface</A
>&nbsp;--&nbsp;Unlocks a previously locked surface.</DT
><DT
><A
HREF="sdlloadbmp.html"
>SDL_LoadBMP</A
>&nbsp;--&nbsp;Load a Windows BMP file into an SDL_Surface.</DT
><DT
><A
HREF="sdlsavebmp.html"
>SDL_SaveBMP</A
>&nbsp;--&nbsp;Save an SDL_Surface as a Windows BMP file.</DT
><DT
><A
HREF="sdlsetcolorkey.html"
>SDL_SetColorKey</A
>&nbsp;--&nbsp;Sets the color key (transparent pixel) in a blittable surface and
RLE acceleration.</DT
><DT
><A
HREF="sdlsetalpha.html"
>SDL_SetAlpha</A
>&nbsp;--&nbsp;Adjust the alpha properties of a surface</DT
><DT
><A
HREF="sdlsetcliprect.html"
>SDL_SetClipRect</A
>&nbsp;--&nbsp;Sets the clipping rectangle for a surface.</DT
><DT
><A
HREF="sdlgetcliprect.html"
>SDL_GetClipRect</A
>&nbsp;--&nbsp;Gets the clipping rectangle for a surface.</DT
><DT
><A
HREF="sdlconvertsurface.html"
>SDL_ConvertSurface</A
>&nbsp;--&nbsp;Converts a surface to the same format as another surface.</DT
><DT
><A
HREF="sdlblitsurface.html"
>SDL_BlitSurface</A
>&nbsp;--&nbsp;This performs a fast blit from the source surface to the destination surface.</DT
><DT
><A
HREF="sdlfillrect.html"
>SDL_FillRect</A
>&nbsp;--&nbsp;This function performs a fast fill of the given rectangle with some color</DT
><DT
><A
HREF="sdldisplayformat.html"
>SDL_DisplayFormat</A
>&nbsp;--&nbsp;Convert a surface to the display format</DT
><DT
><A
HREF="sdldisplayformatalpha.html"
>SDL_DisplayFormatAlpha</A
>&nbsp;--&nbsp;Convert a surface to the display format</DT
><DT
><A
HREF="sdlwarpmouse.html"
>SDL_WarpMouse</A
>&nbsp;--&nbsp;Set the position of the mouse cursor.</DT
><DT
><A
HREF="sdlcreatecursor.html"
>SDL_CreateCursor</A
>&nbsp;--&nbsp;Creates a new mouse cursor.</DT
><DT
><A
HREF="sdlfreecursor.html"
>SDL_FreeCursor</A
>&nbsp;--&nbsp;Frees a cursor created with SDL_CreateCursor.</DT
><DT
><A
HREF="sdlsetcursor.html"
>SDL_SetCursor</A
>&nbsp;--&nbsp;Set the currently active mouse cursor.</DT
><DT
><A
HREF="sdlgetcursor.html"
>SDL_GetCursor</A
>&nbsp;--&nbsp;Get the currently active mouse cursor.</DT
><DT
><A
HREF="sdlshowcursor.html"
>SDL_ShowCursor</A
>&nbsp;--&nbsp;Toggle whether or not the cursor is shown on the screen.</DT
><DT
><A
HREF="sdlglloadlibrary.html"
>SDL_GL_LoadLibrary</A
>&nbsp;--&nbsp;Specify an OpenGL library</DT
><DT
><A
HREF="sdlglgetprocaddress.html"
>SDL_GL_GetProcAddress</A
>&nbsp;--&nbsp;Get the address of a GL function</DT
><DT
><A
HREF="sdlglgetattribute.html"
>SDL_GL_GetAttribute</A
>&nbsp;--&nbsp;Get the value of a special SDL/OpenGL attribute</DT
><DT
><A
HREF="sdlglsetattribute.html"
>SDL_GL_SetAttribute</A
>&nbsp;--&nbsp;Set a special SDL/OpenGL attribute</DT
><DT
><A
HREF="sdlglswapbuffers.html"
>SDL_GL_SwapBuffers</A
>&nbsp;--&nbsp;Swap OpenGL framebuffers/Update Display</DT
><DT
><A
HREF="sdlcreateyuvoverlay.html"
>SDL_CreateYUVOverlay</A
>&nbsp;--&nbsp;Create a YUV video overlay</DT
><DT
><A
HREF="sdllockyuvoverlay.html"
>SDL_LockYUVOverlay</A
>&nbsp;--&nbsp;Lock an overlay</DT
><DT
><A
HREF="sdlunlockyuvoverlay.html"
>SDL_UnlockYUVOverlay</A
>&nbsp;--&nbsp;Unlock an overlay</DT
><DT
><A
HREF="sdldisplayyuvoverlay.html"
>SDL_DisplayYUVOverlay</A
>&nbsp;--&nbsp;Blit the overlay to the display</DT
><DT
><A
HREF="sdlfreeyuvoverlay.html"
>SDL_FreeYUVOverlay</A
>&nbsp;--&nbsp;Free a YUV video overlay</DT
><DT
><A
HREF="sdlglattr.html"
>SDL_GLattr</A
>&nbsp;--&nbsp;SDL GL Attributes</DT
><DT
><A
HREF="sdlrect.html"
>SDL_Rect</A
>&nbsp;--&nbsp;Defines a rectangular area</DT
><DT
><A
HREF="sdlcolor.html"
>SDL_Color</A
>&nbsp;--&nbsp;Format independent color description</DT
><DT
><A
HREF="sdlpalette.html"
>SDL_Palette</A
>&nbsp;--&nbsp;Color palette for 8-bit pixel formats</DT
><DT
><A
HREF="sdlpixelformat.html"
>SDL_PixelFormat</A
>&nbsp;--&nbsp;Stores surface format information</DT
><DT
><A
HREF="sdlsurface.html"
>SDL_Surface</A
>&nbsp;--&nbsp;Graphical Surface Structure</DT
><DT
><A
HREF="sdlvideoinfo.html"
>SDL_VideoInfo</A
>&nbsp;--&nbsp;Video Target information</DT
><DT
><A
HREF="sdloverlay.html"
>SDL_Overlay</A
>&nbsp;--&nbsp;YUV video overlay</DT
></DL
></DIV
><P
>SDL presents a very simple interface to the display framebuffer.  The
framebuffer is represented as an offscreen surface to which you can write
directly.  If you want the screen to show what you have written, call the <A
HREF="sdlupdaterects.html"
>update</A
> function which will
guarantee that the desired portion of the screen is updated.</P
><P
>Before you call any of the SDL video functions, you must first call
<SPAN
CLASS="TOKEN"
>SDL_Init(SDL_INIT_VIDEO)</SPAN
>, which initializes the video
and events in the SDL library.  Check the return code, which should be
<SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, to see if there were any errors in starting up.</P
><P
>If you use both sound and video in your application, you need to call
<SPAN
CLASS="TOKEN"
>SDL_Init(SDL_INIT_AUDIO | SDL_INIT_VIDEO)</SPAN
> before opening the
sound device, otherwise under Win32 DirectX, you won't be able to set
full-screen display modes.</P
><P
>After you have initialized the library, you can start up the video display in a
number of ways.  The easiest way is to pick a common screen resolution and
depth and just initialize the video, checking for errors.  You will probably
get what you want, but SDL may be emulating your requested mode and converting
the display on update.  The best way is to
<A
HREF="sdlgetvideoinfo.html"
>query</A
>, for the best
video mode closest to the desired one, and then
<A
HREF="sdldisplayformat.html"
>convert</A
>
your images to that pixel format.</P
><P
>SDL currently supports any bit depth &gt;= 8 bits per pixel.  8 bpp formats are
considered 8-bit palettized modes, while 12, 15, 16, 24, and 32 bits per pixel
are considered "packed pixel" modes, meaning each pixel contains the RGB color
components packed in the bits of the pixel.</P
><P
>After you have initialized your video mode, you can take the surface that was
returned, and write to it like any other framebuffer, calling the update
routine as you go.</P
><P
>When you have finished your video access and are ready to quit your
application, you should call "<SPAN
CLASS="TOKEN"
>SDL_Quit()</SPAN
>" to shutdown the
video and events.</P
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