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te: Thu, 17 Apr 2003 11:25:26 -0700 From: "Jim" Subject: [SDL] Frame buffer patches... Would seem that GCC 3.2.2 promotes all signed values to unsigned if any single vlaue is unsigned in an expression... for instance when calculating an elo touch position....evertyhign is an (int) except for cach_vinfo.xres which is unsigned. THerefore if y ou reverse the SDL_ELO_MIN_X and SDL_ELO_MAX_X values the resulging negative value pegs the expression to it's max. Attached it the accumu lated patch to typecast the unsigned values to (int) - *dx = (cache_vinfo.xres - (cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); + *dx = ((int)cache_vinfo.xres - ((int)cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); and also to provide quite failure to operations which have the screen currently locked... The touch screen I'm using the original values were exactly opposite of any position I touched on the screen - evaluating the math the expr ession SHOULD have handled reversing the min and max values - and after casting the unsigned .xres and .yres to a signed int - worked well. .. Jim
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Jan 2006 06:36:43 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_CreateCursor" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CreateCursor\- Creates a new mouse cursor\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_Cursor *\fBSDL_CreateCursor\fP\fR(\fBUint8 *data, Uint8 *mask, int w, int h, int hot_x, int hot_y\fR);
.SH "DESCRIPTION"
.PP
Create a cursor using the specified \fBdata\fR and \fBmask\fR (in MSB format)\&. The cursor width must be a multiple of 8 bits\&.
.PP
The cursor is created in black and white according to the following: 
.TP 20
\fBData / Mask\fR
\fBResulting pixel on screen\fR
.TP 20
0 / 1
White
.TP 20
1 / 1
Black
.TP 20
0 / 0
Transparent
.TP 20
1 / 0
Inverted color if possible, black if not\&.
.PP
Cursors created with this function must be freed with \fISDL_FreeCursor\fR\&.
.SH "EXAMPLE"
.PP
.nf
\f(CW/* 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<32; ++row ) {
    for ( col=0; col<32; ++col ) {
      if ( col % 8 ) {
        data[i] <<= 1;
        mask[i] <<= 1;
      } else {
        ++i;
        data[i] = mask[i] = 0;
      }
      switch (image[4+row][col]) {
        case \&'X\&':
          data[i] |= 0x01;
          k[i] |= 0x01;
          break;
        case \&'\&.\&':
          mask[i] |= 0x01;
          break;
        case \&' \&':
          break;
      }
    }
  }
  sscanf(image[4+row], "%d,%d", &hot_x, &hot_y);
  return SDL_CreateCursor(data, mask, 32, 32, hot_x, hot_y);
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_FreeCursor\fP\fR, \fI\fBSDL_SetCursor\fP\fR, \fI\fBSDL_ShowCursor\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01