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<h1>SDL_gfxBlitFunc.h File Reference</h1><code>#include <stdio.h></code><br/>
<code>#include <stdlib.h></code><br/>
<code>#include <SDL.h></code><br/>
<code>#include <SDL_video.h></code><br/>
<p><a href="_s_d_l__gfx_blit_func_8h_source.html">Go to the source code of this file.</a></p>
<table border="0" cellpadding="0" cellspacing="0">
<tr><td colspan="2"><h2>Data Structures</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">struct </td><td class="memItemRight" valign="bottom"><a class="el" href="struct_s_d_l__gfx_blit_info.html">SDL_gfxBlitInfo</a></td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">The structure passed to the low level blit functions. <a href="struct_s_d_l__gfx_blit_info.html#_details">More...</a><br/></td></tr>
<tr><td colspan="2"><h2>Defines</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#ae6b2c815be86ad92310efb40d4b0b30e">GFX_RGBA_FROM_PIXEL</a>(pixel, fmt, r, g, b, a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Unwrap RGBA values from a pixel using mask, shift and loss for surface. <a href="#ae6b2c815be86ad92310efb40d4b0b30e"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a874180f742c36ca537c247036f05c182">GFX_DISEMBLE_RGBA</a>(buf, bpp, fmt, pixel, r, g, b, a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Disassemble buffer pointer into a pixel and separate RGBA values. <a href="#a874180f742c36ca537c247036f05c182"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a64927ca5690904716f7ac93b1fcd4420">GFX_PIXEL_FROM_RGBA</a>(pixel, fmt, r, g, b, a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Wrap a pixel from RGBA values using mask, shift and loss for surface. <a href="#a64927ca5690904716f7ac93b1fcd4420"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a4e59f926fb98a86c01a4ffc5cc20e8d5">GFX_ASSEMBLE_RGBA</a>(buf, bpp, fmt, r, g, b, a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Assemble pixel into buffer pointer from separate RGBA values. <a href="#a4e59f926fb98a86c01a4ffc5cc20e8d5"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#ae3efb9e67172838c394c148a62822da6">GFX_ALPHA_BLEND</a>(sR, sG, sB, A, dR, dG, dB)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Blend the RGB values of two pixels based on a source alpha value. <a href="#ae3efb9e67172838c394c148a62822da6"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a44c498dca765a515f40eecad8f19aac4">GFX_DUFFS_LOOP4</a>(pixel_copy_increment, width)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">4-times unrolled DUFFs loop. <a href="#a44c498dca765a515f40eecad8f19aac4"></a><br/></td></tr>
<tr><td colspan="2"><h2>Functions</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">SDL_GFXBLITFUNC_SCOPE int </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#ab49c560e89b8305051b2e6b347215f03">SDL_gfxBlitRGBA</a> (SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Blitter for RGBA->RGBA blits with alpha adjustment. <a href="#ab49c560e89b8305051b2e6b347215f03"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">SDL_GFXBLITFUNC_SCOPE int </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a4627ae4a0037d0b248bed87f3c294735">SDL_gfxSetAlpha</a> (SDL_Surface *src, Uint8 a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Sets the alpha channel in a 32 bit surface. <a href="#a4627ae4a0037d0b248bed87f3c294735"></a><br/></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">SDL_GFXBLITFUNC_SCOPE int </td><td class="memItemRight" valign="bottom"><a class="el" href="_s_d_l__gfx_blit_func_8h.html#a7c93594525ae349b5cef0156b8f758fc">SDL_gfxMultiplyAlpha</a> (SDL_Surface *src, Uint8 a)</td></tr>
<tr><td class="mdescLeft"> </td><td class="mdescRight">Multiply the alpha channel in a 32bit surface. <a href="#a7c93594525ae349b5cef0156b8f758fc"></a><br/></td></tr>
</table>
<hr/><h2>Define Documentation</h2>
<a class="anchor" id="ae3efb9e67172838c394c148a62822da6"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_ALPHA_BLEND" ref="ae3efb9e67172838c394c148a62822da6" args="(sR, sG, sB, A, dR, dG, dB)" -->
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<td class="memname">#define GFX_ALPHA_BLEND</td>
<td>(</td>
<td class="paramtype">sR, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">sG, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">sB, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">A, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">dR, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">dG, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">dB </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment"><span class="keywordflow">do</span> { \
dR = (((sR-dR)*(A))/255)+dR; \
dG = (((sG-dG)*(A))/255)+dG; \
dB = (((sB-dB)*(A))/255)+dB; \
} <span class="keywordflow">while</span>(0)
</pre></div>
<p>Blend the RGB values of two pixels based on a source alpha value. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00114">114</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<a class="anchor" id="a4e59f926fb98a86c01a4ffc5cc20e8d5"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_ASSEMBLE_RGBA" ref="a4e59f926fb98a86c01a4ffc5cc20e8d5" args="(buf, bpp, fmt, r, g, b, a)" -->
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<td class="memname">#define GFX_ASSEMBLE_RGBA</td>
<td>(</td>
<td class="paramtype">buf, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">bpp, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">fmt, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">r, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">g, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">b, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">a </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment">{ \
Uint32 pixel; \
\
<a class="code" href="_s_d_l__gfx_blit_func_8h.html#a64927ca5690904716f7ac93b1fcd4420" title="Wrap a pixel from RGBA values using mask, shift and loss for surface.">GFX_PIXEL_FROM_RGBA</a>(pixel, fmt, r, g, b, a); \
*((Uint32 *)(buf)) = pixel; \
}
</pre></div>
<p>Assemble pixel into buffer pointer from separate RGBA values. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00103">103</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<a class="anchor" id="a874180f742c36ca537c247036f05c182"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_DISEMBLE_RGBA" ref="a874180f742c36ca537c247036f05c182" args="(buf, bpp, fmt, pixel, r, g, b, a)" -->
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<td class="memname">#define GFX_DISEMBLE_RGBA</td>
<td>(</td>
<td class="paramtype">buf, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">bpp, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">fmt, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">pixel, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">r, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">g, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">b, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">a </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment"><span class="keywordflow">do</span> { \
pixel = *((Uint32 *)(buf)); \
<a class="code" href="_s_d_l__gfx_blit_func_8h.html#ae6b2c815be86ad92310efb40d4b0b30e" title="Unwrap RGBA values from a pixel using mask, shift and loss for surface.">GFX_RGBA_FROM_PIXEL</a>(pixel, fmt, r, g, b, a); \
pixel &= ~fmt->Amask; \
} <span class="keywordflow">while</span>(0)
</pre></div>
<p>Disassemble buffer pointer into a pixel and separate RGBA values. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00082">82</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<a class="anchor" id="a44c498dca765a515f40eecad8f19aac4"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_DUFFS_LOOP4" ref="a44c498dca765a515f40eecad8f19aac4" args="(pixel_copy_increment, width)" -->
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<table class="memname">
<tr>
<td class="memname">#define GFX_DUFFS_LOOP4</td>
<td>(</td>
<td class="paramtype">pixel_copy_increment, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">width </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment">{ <span class="keywordtype">int</span> n = (width+3)/4; \
<span class="keywordflow">switch</span> (width & 3) { \
<span class="keywordflow">case</span> 0: <span class="keywordflow">do</span> { pixel_copy_increment; \
<span class="keywordflow">case</span> 3: pixel_copy_increment; \
<span class="keywordflow">case</span> 2: pixel_copy_increment; \
<span class="keywordflow">case</span> 1: pixel_copy_increment; \
} <span class="keywordflow">while</span> ( --n > 0 ); \
} \
}
</pre></div>
<p>4-times unrolled DUFFs loop. </p>
<p>This is a very useful loop for optimizing blitters. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00126">126</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<a class="anchor" id="a64927ca5690904716f7ac93b1fcd4420"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_PIXEL_FROM_RGBA" ref="a64927ca5690904716f7ac93b1fcd4420" args="(pixel, fmt, r, g, b, a)" -->
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<td class="memname">#define GFX_PIXEL_FROM_RGBA</td>
<td>(</td>
<td class="paramtype">pixel, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">fmt, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">r, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">g, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">b, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">a </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment">{ \
pixel = ((r>>fmt->Rloss)<<fmt->Rshift)| \
((g>>fmt->Gloss)<<fmt->Gshift)| \
((b>>fmt->Bloss)<<fmt->Bshift)| \
((a<<fmt->Aloss)<<fmt->Ashift); \
}
</pre></div>
<p>Wrap a pixel from RGBA values using mask, shift and loss for surface. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00092">92</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<a class="anchor" id="ae6b2c815be86ad92310efb40d4b0b30e"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::GFX_RGBA_FROM_PIXEL" ref="ae6b2c815be86ad92310efb40d4b0b30e" args="(pixel, fmt, r, g, b, a)" -->
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<td class="memname">#define GFX_RGBA_FROM_PIXEL</td>
<td>(</td>
<td class="paramtype">pixel, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">fmt, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">r, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">g, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">b, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">a </td>
<td class="paramname"></td>
<td> ) </td>
<td></td>
</tr>
</table>
</div>
<div class="memdoc">
<b>Value:</b><div class="fragment"><pre class="fragment">{ \
r = ((pixel&fmt->Rmask)>>fmt->Rshift)<<fmt->Rloss; \
g = ((pixel&fmt->Gmask)>>fmt->Gshift)<<fmt->Gloss; \
b = ((pixel&fmt->Bmask)>>fmt->Bshift)<<fmt->Bloss; \
a = ((pixel&fmt->Amask)>>fmt->Ashift)<<fmt->Aloss; \
}
</pre></div>
<p>Unwrap RGBA values from a pixel using mask, shift and loss for surface. </p>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html#l00071">71</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8h_source.html">SDL_gfxBlitFunc.h</a>.</p>
</div>
</div>
<hr/><h2>Function Documentation</h2>
<a class="anchor" id="ab49c560e89b8305051b2e6b347215f03"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::SDL_gfxBlitRGBA" ref="ab49c560e89b8305051b2e6b347215f03" args="(SDL_Surface *src, SDL_Rect *srcrect, SDL_Surface *dst, SDL_Rect *dstrect)" -->
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<td class="memname">SDL_GFXBLITFUNC_SCOPE int SDL_gfxBlitRGBA </td>
<td>(</td>
<td class="paramtype">SDL_Surface * </td>
<td class="paramname"> <em>src</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">SDL_Rect * </td>
<td class="paramname"> <em>srcrect</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">SDL_Surface * </td>
<td class="paramname"> <em>dst</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">SDL_Rect * </td>
<td class="paramname"> <em>dstrect</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td></td>
</tr>
</table>
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<div class="memdoc">
<p>Blitter for RGBA->RGBA blits with alpha adjustment. </p>
<p>Verifies the input 'src' and 'dst' surfaces and rectangles and performs blit. The destination clip rectangle is honored.</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>src</em> </td><td>The source surface. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>srcrect</em> </td><td>The source rectangle. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>dst</em> </td><td>The destination surface. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>dstrect</em> </td><td>The destination rectangle.</td></tr>
</table>
</dd>
</dl>
<dl class="return"><dt><b>Returns:</b></dt><dd>Returns 1 if blit was performed, 0 otherwise, or -1 if an error occured. </dd></dl>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html#l00390">390</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html">SDL_gfxBlitFunc.c</a>.</p>
</div>
</div>
<a class="anchor" id="a7c93594525ae349b5cef0156b8f758fc"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::SDL_gfxMultiplyAlpha" ref="a7c93594525ae349b5cef0156b8f758fc" args="(SDL_Surface *src, Uint8 a)" -->
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<td class="memname">SDL_GFXBLITFUNC_SCOPE int SDL_gfxMultiplyAlpha </td>
<td>(</td>
<td class="paramtype">SDL_Surface * </td>
<td class="paramname"> <em>src</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">Uint8 </td>
<td class="paramname"> <em>a</em></td><td> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td><td></td>
</tr>
</table>
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<div class="memdoc">
<p>Multiply the alpha channel in a 32bit surface. </p>
<p>Helper function that multiplies the alpha channel in a 32 bit surface with a constant value. The final alpha is always scaled to the range 0-255 (i.e. the factor is a/256). Only 32 bit surfaces can be used with this function.</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>src</em> </td><td>Pointer to the target surface to change. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>a</em> </td><td>The alpha value to multiply with.</td></tr>
</table>
</dd>
</dl>
<dl class="return"><dt><b>Returns:</b></dt><dd>Returns 1 if alpha was changed, 0 otherwise. </dd></dl>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html#l00547">547</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html">SDL_gfxBlitFunc.c</a>.</p>
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<a class="anchor" id="a4627ae4a0037d0b248bed87f3c294735"></a><!-- doxytag: member="SDL_gfxBlitFunc.h::SDL_gfxSetAlpha" ref="a4627ae4a0037d0b248bed87f3c294735" args="(SDL_Surface *src, Uint8 a)" -->
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<td class="memname">SDL_GFXBLITFUNC_SCOPE int SDL_gfxSetAlpha </td>
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<td class="paramtype">SDL_Surface * </td>
<td class="paramname"> <em>src</em>, </td>
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<td class="paramtype">Uint8 </td>
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<p>Sets the alpha channel in a 32 bit surface. </p>
<p>Helper function that sets the alpha channel in a 32 bit surface to a constant value. Only 32 bit surfaces can be used with this function.</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table border="0" cellspacing="2" cellpadding="0">
<tr><td valign="top"></td><td valign="top"><em>src</em> </td><td>Pointer to the target surface to change. </td></tr>
<tr><td valign="top"></td><td valign="top"><em>a</em> </td><td>The alpha value to set.</td></tr>
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<dl class="return"><dt><b>Returns:</b></dt><dd>Returns 1 if alpha was changed, 0 otherwise. </dd></dl>
<p>Definition at line <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html#l00503">503</a> of file <a class="el" href="_s_d_l__gfx_blit_func_8c_source.html">SDL_gfxBlitFunc.c</a>.</p>
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