view docs/html/sdlcreatecursor.html @ 4355:9b464226e541 SDL-1.2

Fixed bug #855 Ludwig Nussel 2009-10-18 06:31:52 PDT an mprotect call was added to fix bug 528. However that results in a buffer that allows writing and code execution. Ie the no-execute security features of modern operating systems are defeated this way. Two mprotect calls are needed. One to make the buffer executable but not writeable when done and another one to make the buffer writeable again if the content needs to be changed.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 18 Oct 2009 17:31:37 +0000
parents 355632dca928
children
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>SDL_CreateCursor</TITLE
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><H1
><A
NAME="SDLCREATECURSOR"
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>SDL_CreateCursor</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2487"
></A
><H2
>Name</H2
>SDL_CreateCursor&nbsp;--&nbsp;Creates a new mouse cursor.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN2490"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN2491"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>SDL_Cursor *<B
CLASS="FSFUNC"
>SDL_CreateCursor</B
></CODE
>(Uint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2497"
></A
><H2
>Description</H2
><P
>Create a cursor using the specified <TT
CLASS="PARAMETER"
><I
>data</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>mask</I
></TT
> (in MSB format).
The cursor width must be a multiple of 8 bits.</P
><P
>The cursor is created in black and white according to the following:
<DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN2503"
></A
><P
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><THEAD
><TR
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Data / Mask</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Resulting pixel on screen</TH
></TR
></THEAD
><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>0 / 1</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>White</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>1 / 1</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Black</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>0 / 0</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Transparent</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>1 / 0</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Inverted color if possible, black if not.</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
></P
><P
>Cursors created with this function must be freed with
<A
HREF="sdlfreecursor.html"
>SDL_FreeCursor</A
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2524"
></A
><H2
>Example</H2
><PRE
CLASS="PROGRAMLISTING"
>/* Stolen from the mailing list */
/* Creates a new mouse cursor from an XPM */


/* XPM */
static const char *arrow[] = {
  /* width height num_colors chars_per_pixel */
  "    32    32        3            1",
  /* colors */
  "X c #000000",
  ". c #ffffff",
  "  c None",
  /* pixels */
  "X                               ",
  "XX                              ",
  "X.X                             ",
  "X..X                            ",
  "X...X                           ",
  "X....X                          ",
  "X.....X                         ",
  "X......X                        ",
  "X.......X                       ",
  "X........X                      ",
  "X.....XXXXX                     ",
  "X..X..X                         ",
  "X.X X..X                        ",
  "XX  X..X                        ",
  "X    X..X                       ",
  "     X..X                       ",
  "      X..X                      ",
  "      X..X                      ",
  "       XX                       ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "                                ",
  "0,0"
};

static SDL_Cursor *init_system_cursor(const char *image[])
{
  int i, row, col;
  Uint8 data[4*32];
  Uint8 mask[4*32];
  int hot_x, hot_y;

  i = -1;
  for ( row=0; row&#60;32; ++row ) {
    for ( col=0; col&#60;32; ++col ) {
      if ( col % 8 ) {
        data[i] &#60;&#60;= 1;
        mask[i] &#60;&#60;= 1;
      } else {
        ++i;
        data[i] = mask[i] = 0;
      }
      switch (image[4+row][col]) {
        case 'X':
          data[i] |= 0x01;
          mask[i] |= 0x01;
          break;
        case '.':
          mask[i] |= 0x01;
          break;
        case ' ':
          break;
      }
    }
  }
  sscanf(image[4+row], "%d,%d", &#38;hot_x, &#38;hot_y);
  return SDL_CreateCursor(data, mask, 32, 32, hot_x, hot_y);
}</PRE
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlfreecursor.html"
><TT
CLASS="FUNCTION"
>SDL_FreeCursor</TT
></A
>,
<A
HREF="sdlsetcursor.html"
><TT
CLASS="FUNCTION"
>SDL_SetCursor</TT
></A
>,
<A
HREF="sdlshowcursor.html"
><TT
CLASS="FUNCTION"
>SDL_ShowCursor</TT
></A
></P
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