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view docs/html/sdlcreatecursor.html @ 3880:74e828c64315 SDL-1.2

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Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:45:37 +0000
parents 355632dca928
children
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<HTML
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><TITLE
>SDL_CreateCursor</TITLE
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><H1
><A
NAME="SDLCREATECURSOR"
></A
>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
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2527"
></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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