view docs/html/sdlmousebuttonevent.html @ 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 355632dca928
children
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><H1
><A
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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
></DIV
><DIV
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><A
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></A
><H2
>Structure Data</H2
><DIV
CLASS="INFORMALTABLE"
><A
NAME="AEN4152"
></A
><P
></P
><TABLE
BORDER="0"
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><TBODY
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>type</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><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
ALIGN="LEFT"
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>The mouse button index (SDL_BUTTON_LEFT, SDL_BUTTON_MIDDLE, SDL_BUTTON_RIGHT)</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>state</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="LITERAL"
>SDL_PRESSED</TT
> or <TT
CLASS="LITERAL"
>SDL_RELEASED</TT
></TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
><TT
CLASS="STRUCTFIELD"
><I
>x</I
></TT
>, <TT
CLASS="STRUCTFIELD"
><I
>y</I
></TT
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>The X/Y coordinates of the mouse at press/release time</TD
></TR
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><P
></P
></DIV
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><DIV
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><A
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></A
><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
HREF="sdlkeyboardevent.html"
><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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><H2
>See Also</H2
><P
><A
HREF="sdlevent.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Event</SPAN
></A
>,
<A
HREF="sdlmousemotionevent.html"
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>SDL_MouseMotionEvent</SPAN
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