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<p>
Next: <a href="Blend-Modes.html" accesskey="n" rel="next">Blend Modes</a>, Previous: <a href="Surfaces.html" accesskey="p" rel="prev">Surfaces</a>, Up: <a href="API-Reference.html" accesskey="u" rel="up">API Reference</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p>
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<hr>
<span id="Rendering-1"></span><h3 class="section">3.7 Rendering</h3>
<div class="example">
<pre class="example">(use-modules (sdl2 render))
</pre></div>
<dl>
<dt id="index-make_002drenderer">Procedure: <strong>make-renderer</strong> <em>window [#:optional flags='(accelerated vsync)]</em></dt>
<dd><p>Return a new renderer for <var>window</var> created with the options specified
in <var>flags</var>, a list of symbols. The valid symbols that may appear in
<var>flags</var> are:
</p>
<ul>
<li> software, to use a software renderer fallback
</li><li> accelerated, to use hardware acceleration
</li><li> vsync, to synchronize rendering with the monitor’s refresh rate
</li><li> texture, for render to texture support
</li></ul>
</dd></dl>
<dl>
<dt id="index-renderer_003f">Procedure: <strong>renderer?</strong> <em>r</em></dt>
<dd><p>Return <code>#t</code> if <var>r</var> is a renderer.
</p></dd></dl>
<dl>
<dt id="index-delete_002drenderer_0021">Procedure: <strong>delete-renderer!</strong> <em>renderer</em></dt>
<dd><p>Delete the rendering context <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-call_002dwith_002drenderer">Procedure: <strong>call-with-renderer</strong> <em>renderer proc</em></dt>
<dd><p>Call <var>proc</var>, passing it <var>renderer</var> and closing <var>renderer</var> upon exit
of <var>proc</var>.
</p></dd></dl>
<dl>
<dt id="index-clear_002drenderer">Procedure: <strong>clear-renderer</strong> <em>renderer</em></dt>
<dd><p>Clear the rendering target <var>renderer</var> with the current drawing color.
</p></dd></dl>
<dl>
<dt id="index-present_002drenderer">Procedure: <strong>present-renderer</strong> <em>renderer</em></dt>
<dd><p>Display <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-renderer_002dinteger_002dscale">Procedure: <strong>renderer-integer-scale</strong> <em>renderer</em></dt>
<dd><p>Returns <code>#t</code> if <var>renderer</var> currently uses integer scaling and
<code>#f</code> otherwise. Integer scaling can be used together with
logical size to effectively restrict the drawing region to an area
even if the window is larger than that.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002dinteger_002dscale_0021">Procedure: <strong>set-renderer-integer-scale!</strong> <em>renderer enable?</em></dt>
<dd><p>If <var>enable?</var> is <code>#t</code>, enable integer scaling, otherwise
disable it.
</p></dd></dl>
<dl>
<dt id="index-renderer_002dlogical_002dsize">Procedure: <strong>renderer-logical-size</strong> <em>renderer</em></dt>
<dd><p>Return the current logical size used by <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002dlogical_002dsize_0021">Procedure: <strong>set-renderer-logical-size!</strong> <em>renderer width height</em></dt>
<dd><p>Set the logical size of <var>renderer</var> to <var>width</var> x <var>height</var>.
</p></dd></dl>
<dl>
<dt id="index-renderer_002dscale">Procedure: <strong>renderer-scale</strong> <em>renderer</em></dt>
<dd><p>Return the scaling factors <code>(X Y)</code> used by <var>renderer</var> to
scale coordinates.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002dscale_0021">Procedure: <strong>set-renderer-scale!</strong> <em>renderer scale-x scale-y</em></dt>
<dd><p>Set the factors by which <var>renderer</var> scales coordinates according
to the scaling factors <var>scale-x</var> and <var>scale-y</var>.
</p></dd></dl>
<dl>
<dt id="index-renderer_002dviewport">Procedure: <strong>renderer-viewport</strong> <em>renderer</em></dt>
<dd><p>Return the rectangle that <var>renderer</var> currently draws on. If the
entire region is used, all values of that rectangle will be 0.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002dviewport_0021">Procedure: <strong>set-renderer-viewport!</strong> <em>renderer rect</em></dt>
<dd><p>Set the drawing area for <var>renderer</var> to <var>rect</var>.
</p></dd></dl>
<dl>
<dt id="index-render_002dcopy">Procedure: <strong>render-copy</strong> <em>renderer texture [#:angle 0] [#:srcrect] [#:dstrect] [#:center]</em></dt>
<dd><p>Copy <var>texture</var> to the rendering target of <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002ddraw_002dcolor_0021">Procedure: <strong>set-renderer-draw-color!</strong> <em>renderer r g b a</em></dt>
<dd><p>Set color of <var>renderer</var> to the 32-bit color defined by the 8-bit
color channels <var>r</var>, <var>g</var>, <var>b</var>, <var>a</var>. Each color channel
value is in the range [0, 255].
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002ddraw_002dblend_002dmode_0021">Procedure: <strong>set-renderer-draw-blend-mode!</strong> <em>renderer blend-mode</em></dt>
<dd><p>Set blend mode of <var>renderer</var> to <var>blend-mode</var>. See <a href="Blend-Modes.html">Blend Modes</a> for more information.
</p></dd></dl>
<dl>
<dt id="index-set_002drenderer_002dtarget_0021">Procedure: <strong>set-renderer-target!</strong> <em>renderer texture</em></dt>
<dd><p>Sets the render target for <var>renderer</var> to <var>texture</var>, making all
comming draw requests redirect to <var>texture</var>.
</p>
<p>Pass <code>#f</code> to reset it to the default target.
</p></dd></dl>
<dl>
<dt id="index-renderer_002dtarget">Procedure: <strong>renderer-target</strong> <em>renderer</em></dt>
<dd><p>Returns the current render target of <var>renderer</var> or <code>#f</code> if
it’s a texture.
</p></dd></dl>
<dl>
<dt id="index-draw_002dline">Procedure: <strong>draw-line</strong> <em>renderer x1 y1 x2 y2</em></dt>
<dd><p>Draw a line from (<var>x1</var>, <var>y1</var>) to (<var>x2</var>, <var>y2</var>) on the
current rendering target of <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-draw_002dlines">Procedure: <strong>draw-lines</strong> <em>renderer points</em></dt>
<dd><p>Draw a series of connected lines from <var>points</var> on the current
rendering target of <var>renderer</var>. Optionally, for best performance,
<var>points</var> may instead be a bytevector packed with signed 32 bit
integers, 2 per point (x and y).
</p></dd></dl>
<dl>
<dt id="index-draw_002dpoint">Procedure: <strong>draw-point</strong> <em>renderer x y</em></dt>
<dd><p>Draw a point at (<var>x</var>, <var>y</var>) on the current rendering target
of <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-draw_002dpoints">Procedure: <strong>draw-points</strong> <em>renderer points</em></dt>
<dd><p>Draw a multiple points from <var>points</var> on the current rendering
target of <var>renderer</var>. Optionally, for best performance,
<var>points</var> may instead be a bytevector packed with signed 32 bit
integers, 2 per point (x and y).
</p></dd></dl>
<dl>
<dt id="index-draw_002drect">Procedure: <strong>draw-rect</strong> <em>renderer rectangle</em></dt>
<dd><p>Draw the outline of <var>rectangle</var> onto renderer.
</p></dd></dl>
<dl>
<dt id="index-draw_002drects">Procedure: <strong>draw-rects</strong> <em>renderer rects</em></dt>
<dd><p>Draw the outline of all rects in the list <var>rects</var> onto
<var>renderer</var>. Optionally, for best performance, <var>rects</var> may
instead be a bytevector packed with signed 32 bit integers, 4 per rect
(x, y, width, height).
</p></dd></dl>
<dl>
<dt id="index-fill_002drect-1">Procedure: <strong>fill-rect</strong> <em>renderer rectangle</em></dt>
<dd><p>Fill <var>rectangle</var> onto <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-fill_002drects">Procedure: <strong>fill-rects</strong> <em>renderer rects</em></dt>
<dd><p>Fill the list <var>rects</var> onto <var>renderer</var>. Optionally, for best
performance, <var>rects</var> may instead be a bytevector packed with
signed 32 bit integers, 4 per rect (x, y, width, height).
</p></dd></dl>
<dl>
<dt id="index-make_002dtexture">Procedure: <strong>make-texture</strong> <em>renderer format access width height</em></dt>
<dd><p>Returns a new texture for <var>renderer</var> with pixel <var>format</var>.
<var>access</var> is one of the symbols:
</p>
<ul>
<li> static, changes rarely, not lockable
</li><li> streaming, changes frequently, lockable
</li><li> target, can be used as a render target
requires that renderer was created with the <code>texture</code> flag.
</li></ul>
</dd></dl>
<dl>
<dt id="index-query_002dtexture">Procedure: <strong>query-texture</strong> <em>texture</em></dt>
<dd><p>Return 4 values for the format, access, width and height of a texture.
</p></dd></dl>
<dl>
<dt id="index-surface_002d_003etexture">Procedure: <strong>surface->texture</strong> <em>renderer surface</em></dt>
<dd><p>Convert <var>surface</var> to a texture suitable for <var>renderer</var>.
</p></dd></dl>
<dl>
<dt id="index-delete_002dtexture_0021">Procedure: <strong>delete-texture!</strong> <em>texture</em></dt>
<dd><p>Free the memory used by <var>texture</var>.
</p></dd></dl>
<dl>
<dt id="index-update_002dtexture">Procedure: <strong>update-texture</strong> <em>texture rect pixels pitch</em></dt>
<dd><p>Update the subsection of <var>texture</var> defined by <var>rect</var> with new
pixel data in the <var>pixels</var> bytevector. <var>pitch</var> represents the
number of bytes in a row of pixel data, including any padding between
rows. This is a fairly slow process: Better to use the lock/unlock
mechanism in streaming textures.
</p></dd></dl>
<dl>
<dt id="index-texture_002dcolor_002dmod">Procedure: <strong>texture-color-mod</strong> <em>texture</em></dt>
<dd><p>Get color mod of <var>texture</var> as a list of the integers.
</p></dd></dl>
<dl>
<dt id="index-texture_002dalpha_002dmod">Procedure: <strong>texture-alpha-mod</strong> <em>texture</em></dt>
<dd><p>Get alpha mod of <var>texture</var> as a single integer.
</p></dd></dl>
<dl>
<dt id="index-set_002dtexture_002dcolor_002dmod_0021">Procedure: <strong>set-texture-color-mod!</strong> <em>texture r g b</em></dt>
<dd><p>Set the color mod of <var>texture</var>.
</p></dd></dl>
<dl>
<dt id="index-set_002dtexture_002dalpha_002dmod_0021">Procedure: <strong>set-texture-alpha-mod!</strong> <em>texture a</em></dt>
<dd><p>Set the alpha mod of <var>texture</var>.
</p></dd></dl>
<dl>
<dt id="index-set_002dtexture_002dblend_002dmode_0021">Procedure: <strong>set-texture-blend-mode!</strong> <em>texture blend-mode</em></dt>
<dd><p>Set the blend of <var>texture</var> to <var>blend-mode</var>. See <a href="Blend-Modes.html">Blend Modes</a> for more information.
</p></dd></dl>
<hr>
<div class="header">
<p>
Next: <a href="Blend-Modes.html" accesskey="n" rel="next">Blend Modes</a>, Previous: <a href="Surfaces.html" accesskey="p" rel="prev">Surfaces</a>, Up: <a href="API-Reference.html" accesskey="u" rel="up">API Reference</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p>
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