view docs/html/sdlmousebuttonevent.html @ 1259:36f24cdfcda7

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 355632dca928
children
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>SDL_MouseButtonEvent</TITLE
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><H1
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>SDL_MouseButtonEvent</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4144"
></A
><H2
>Name</H2
>SDL_MouseButtonEvent&nbsp;--&nbsp;Mouse button event structure</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4147"
></A
><H2
>Structure Definition</H2
><PRE
CLASS="PROGRAMLISTING"
>typedef struct{
  Uint8 type;
  Uint8 button;
  Uint8 state;
  Uint16 x, y;
} SDL_MouseButtonEvent;</PRE
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><H2
>Structure Data</H2
><DIV
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><P
></P
><TABLE
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><TR
><TD
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><TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
></TD
><TD
ALIGN="LEFT"
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><TT
CLASS="LITERAL"
>SDL_MOUSEBUTTONDOWN</TT
> or <TT
CLASS="LITERAL"
>SDL_MOUSEBUTTONUP</TT
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>button</I
></TT
></TD
><TD
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>The mouse button index (SDL_BUTTON_LEFT, SDL_BUTTON_MIDDLE, SDL_BUTTON_RIGHT)</TD
></TR
><TR
><TD
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><TT
CLASS="STRUCTFIELD"
><I
>state</I
></TT
></TD
><TD
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><TT
CLASS="LITERAL"
>SDL_PRESSED</TT
> or <TT
CLASS="LITERAL"
>SDL_RELEASED</TT
></TD
></TR
><TR
><TD
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><TT
CLASS="STRUCTFIELD"
><I
>x</I
></TT
>, <TT
CLASS="STRUCTFIELD"
><I
>y</I
></TT
></TD
><TD
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>The X/Y coordinates of the mouse at press/release time</TD
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><H2
>Description</H2
><P
><SPAN
CLASS="STRUCTNAME"
>SDL_MouseButtonEvent</SPAN
> is a member of the <A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
> union and is used when an event of type <TT
CLASS="LITERAL"
>SDL_MOUSEBUTTONDOWN</TT
> or <TT
CLASS="LITERAL"
>SDL_MOUSEBUTTONUP</TT
> is reported.</P
><P
>When a mouse button press or release is detected then number of the button pressed (from 1 to 255, with 1 usually being the left button and 2 the right) is placed into <TT
CLASS="STRUCTFIELD"
><I
>button</I
></TT
>, the position of the mouse when this event occured is stored in the <TT
CLASS="STRUCTFIELD"
><I
>x</I
></TT
> and the <TT
CLASS="STRUCTFIELD"
><I
>y</I
></TT
> fields. Like <A
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><SPAN
CLASS="STRUCTNAME"
>SDL_KeyboardEvent</SPAN
></A
>, information on whether the event was a press or a release event is stored in both the <TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
> and <TT
CLASS="STRUCTFIELD"
><I
>state</I
></TT
> fields, but this should be obvious.</P
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>See Also</H2
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>SDL_Event</SPAN
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>,
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