view docs/man3/SDL_UserEvent.3 @ 3333:b334b4f7dfa0

[SDL] Bad math in SDL_RenderCopy Mason Wheeler to sdl When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this: if (dstrect->w != real_dstrect.w) { int deltax = (dstrect->x - real_dstrect.x); int deltaw = (dstrect->w - real_dstrect.w); real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w; real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w; } if (dstrect->h != real_dstrect.h) { int deltay = (dstrect->y - real_dstrect.y); int deltah = (dstrect->h - real_dstrect.h); real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h; real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author Sam Lantinga <slouken@libsdl.org>
date Sat, 03 Oct 2009 16:23:16 +0000
parents 546f7c1eb755
children 1238da4a7112
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.TH "SDL_UserEvent" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_UserEvent \- A user-defined event type
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 type;
  int code;
  void *data1;
  void *data2;
} SDL_UserEvent;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBtype\fR
\fBSDL_USEREVENT\fP through to \fBSDL_NUMEVENTS-1\fP
.TP 20
\fBcode\fR
User defined event code
.TP 20
\fBdata1\fR
User defined data pointer
.TP 20
\fBdata2\fR
User defined data pointer
.SH "DESCRIPTION"
.PP
\fBSDL_UserEvent\fR is in the \fBuser\fR member of the structure \fI\fBSDL_Event\fR\fR\&. This event is unique, it is never created by SDL but only by the user\&. The event can be pushed onto the event queue using \fI\fBSDL_PushEvent\fP\fR\&. The contents of the structure members or completely up to the programmer, the only requirement is that \fBtype\fR is a value from \fBSDL_USEREVENT\fP to \fBSDL_NUMEVENTS-1\fP (inclusive)\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWSDL_Event event;

event\&.type = SDL_USEREVENT;
event\&.user\&.code = my_event_code;
event\&.user\&.data1 = significant_data;
event\&.user\&.data2 = 0;
SDL_PushEvent(&event);\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_Event\fR\fR, \fI\fBSDL_PushEvent\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00