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<h2><span class="refentrytitle"><a name="GwyGradient.top_of_page"></a>GwyGradient</span></h2>
<p>GwyGradient — A map from numbers to RGBA colors</p>
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<td valign="top" align="right"></td>
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<div class="refsynopsisdiv">
<a name="GwyGradient.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <libdraw/gwydraw.h>
struct <a class="link" href="GwyGradient.html#GwyGradient-struct" title="struct GwyGradient">GwyGradient</a>;
struct <a class="link" href="GwyGradient.html#GwyGradientClass" title="struct GwyGradientClass">GwyGradientClass</a>;
#define <a class="link" href="GwyGradient.html#GWY-GRADIENT-DEFAULT:CAPS" title="GWY_GRADIENT_DEFAULT">GWY_GRADIENT_DEFAULT</a>
<a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint">GwyGradientPoint</a>;
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-get-color" title="gwy_gradient_get_color ()">gwy_gradient_get_color</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> x</code></em>,
<em class="parameter"><code><a class="link" href="libgwydraw-GwyRGBA.html#GwyRGBA" title="GwyRGBA"><span class="type">GwyRGBA</span></a> *color</code></em>);
const <a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#guchar"><span class="returnvalue">guchar</span></a> * <a class="link" href="GwyGradient.html#gwy-gradient-get-samples" title="gwy_gradient_get_samples ()">gwy_gradient_get_samples</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> *nsamples</code></em>);
<a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#guchar"><span class="returnvalue">guchar</span></a> * <a class="link" href="GwyGradient.html#gwy-gradient-sample" title="gwy_gradient_sample ()">gwy_gradient_sample</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> nsamples</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#guchar"><span class="type">guchar</span></a> *samples</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-sample-to-pixbuf" title="gwy_gradient_sample_to_pixbuf ()">gwy_gradient_sample_to_pixbuf</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/gdk-pixbuf/gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>);
<a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="returnvalue">gint</span></a> <a class="link" href="GwyGradient.html#gwy-gradient-get-npoints" title="gwy_gradient_get_npoints ()">gwy_gradient_get_npoints</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>);
<a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="returnvalue">GwyGradientPoint</span></a> <a class="link" href="GwyGradient.html#gwy-gradient-get-point" title="gwy_gradient_get_point ()">gwy_gradient_get_point</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-set-point" title="gwy_gradient_set_point ()">gwy_gradient_set_point</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-set-point-color" title="gwy_gradient_set_point_color ()">gwy_gradient_set_point_color</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="libgwydraw-GwyRGBA.html#GwyRGBA" title="GwyRGBA"><span class="type">GwyRGBA</span></a> *color</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-insert-point" title="gwy_gradient_insert_point ()">gwy_gradient_insert_point</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);
<a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="returnvalue">gint</span></a> <a class="link" href="GwyGradient.html#gwy-gradient-insert-point-sorted" title="gwy_gradient_insert_point_sorted ()">gwy_gradient_insert_point_sorted</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-delete-point" title="gwy_gradient_delete_point ()">gwy_gradient_delete_point</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-reset" title="gwy_gradient_reset ()">gwy_gradient_reset</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>);
const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="returnvalue">GwyGradientPoint</span></a> * <a class="link" href="GwyGradient.html#gwy-gradient-get-points" title="gwy_gradient_get_points ()">gwy_gradient_get_points</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> *npoints</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-set-points" title="gwy_gradient_set_points ()">gwy_gradient_set_points</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="http://developer.gnome.org/doc/API/2.0/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> npoints</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *points</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GwyGradient.html#gwy-gradient-set-from-samples" title="gwy_gradient_set_from_samples ()">gwy_gradient_set_from_samples</a> (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> nsamples</code></em>,
<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guchar"><span class="type">guchar</span></a> *samples</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> threshold</code></em>);
<a href="../libgwyddion/GwyInventory.html"><span class="returnvalue">GwyInventory</span></a> * <a class="link" href="GwyGradient.html#gwy-gradients" title="gwy_gradients ()">gwy_gradients</a> (<em class="parameter"><code><span class="type">void</span></code></em>);
<a class="link" href="GwyGradient.html" title="GwyGradient"><span class="returnvalue">GwyGradient</span></a> * <a class="link" href="GwyGradient.html#gwy-gradients-get-gradient" title="gwy_gradients_get_gradient ()">gwy_gradients_get_gradient</a> (<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *name</code></em>);
</pre>
</div>
<div class="refsect1">
<a name="GwyGradient.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="synopsis">
<a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject">GObject</a>
+----<a href="../libgwyddion/GwyResource.html">GwyResource</a>
+----GwyGradient
</pre>
</div>
<div class="refsect1">
<a name="GwyGradient.description"></a><h2>Description</h2>
<p>
Gradient is a map from interval [0,1] to RGB(A) color space. Each gradient
is defined by an ordered set of color points, the first of them is always at
0.0, the last at 1.0 (thus each gradient must consist of at least two
points). Between them, the color is interpolated. Color points of
modifiable gradients (see <a href="../libgwyddion/GwyResource.html"><span class="type">GwyResource</span></a>) can be edited with functions like
<a class="link" href="GwyGradient.html#gwy-gradient-insert-point" title="gwy_gradient_insert_point ()"><code class="function">gwy_gradient_insert_point()</code></a>, <a class="link" href="GwyGradient.html#gwy-gradient-set-point-color" title="gwy_gradient_set_point_color ()"><code class="function">gwy_gradient_set_point_color()</code></a>, or
<a class="link" href="GwyGradient.html#gwy-gradient-set-points" title="gwy_gradient_set_points ()"><code class="function">gwy_gradient_set_points()</code></a>.
</p>
<p>
Gradient objects can be obtained from <a class="link" href="GwyGradient.html#gwy-gradients-get-gradient" title="gwy_gradients_get_gradient ()"><code class="function">gwy_gradients_get_gradient()</code></a>. New
gradients can be created with <a href="../libgwyddion/GwyInventory.html#gwy-inventory-new-item"><code class="function">gwy_inventory_new_item()</code></a> on the <a href="../libgwyddion/GwyInventory.html"><span class="type">GwyInventory</span></a>
returned by <a class="link" href="GwyGradient.html#gwy-gradients" title="gwy_gradients ()"><code class="function">gwy_gradients()</code></a>.
</p>
</div>
<div class="refsect1">
<a name="GwyGradient.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GwyGradient-struct"></a><h3>struct GwyGradient</h3>
<pre class="programlisting">struct GwyGradient;</pre>
<p>
<a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> struct contains private data only and should be accessed
using the functions below.
</p>
</div>
<hr>
<div class="refsect2">
<a name="GwyGradientClass"></a><h3>struct GwyGradientClass</h3>
<pre class="programlisting">struct GwyGradientClass;</pre>
<p>
<a class="link" href="GwyGradient.html#GwyGradientClass" title="struct GwyGradientClass"><span class="type">GwyGradientClass</span></a> does not contain any public members.
</p>
</div>
<hr>
<div class="refsect2">
<a name="GWY-GRADIENT-DEFAULT:CAPS"></a><h3>GWY_GRADIENT_DEFAULT</h3>
<pre class="programlisting">#define GWY_GRADIENT_DEFAULT "Gray"
</pre>
<p>
The name of the default gray color gradient.
</p>
<p>
It is guaranteed to always exist.
</p>
<p>
Note this is not the same as user's default gradient which corresponds to
the default item in <a class="link" href="GwyGradient.html#gwy-gradients" title="gwy_gradients ()"><code class="function">gwy_gradients()</code></a> inventory and it changes over time.
</p>
</div>
<hr>
<div class="refsect2">
<a name="GwyGradientPoint"></a><h3>GwyGradientPoint</h3>
<pre class="programlisting">typedef struct {
gdouble x;
GwyRGBA color;
} GwyGradientPoint;
</pre>
<p>
Gradient color point struct.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> <em class="structfield"><code><a name="GwyGradientPoint.x"></a>x</code></em>;</span></p></td>
<td>Color point position (in interval [0,1]).</td>
</tr>
<tr>
<td><p><span class="term"><a class="link" href="libgwydraw-GwyRGBA.html#GwyRGBA" title="GwyRGBA"><span class="type">GwyRGBA</span></a> <em class="structfield"><code><a name="GwyGradientPoint.color"></a>color</code></em>;</span></p></td>
<td>The color at position <em class="parameter"><code>x</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-get-color"></a><h3>gwy_gradient_get_color ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_get_color (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> x</code></em>,
<em class="parameter"><code><a class="link" href="libgwydraw-GwyRGBA.html#GwyRGBA" title="GwyRGBA"><span class="type">GwyRGBA</span></a> *color</code></em>);</pre>
<p>
Computes the color at a given position of a color gradient.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>x</code></em> :</span></p></td>
<td>Position in gradient, in range 0..1.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>color</code></em> :</span></p></td>
<td>Color to fill with interpolated color at position <em class="parameter"><code>x</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-get-samples"></a><h3>gwy_gradient_get_samples ()</h3>
<pre class="programlisting">const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guchar"><span class="returnvalue">guchar</span></a> * gwy_gradient_get_samples (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> *nsamples</code></em>);</pre>
<p>
Returns color gradient sampled to integers in <span class="type">GdkPixbuf-like</span> scheme.
</p>
<p>
The returned samples are owned by <em class="parameter"><code>gradient</code></em> and must not be modified or
freed. They are automatically updated when the gradient changes, although
their number never changes. The returned pointer is valid only as long
as the gradient used, indicated by <a href="../libgwyddion/GwyResource.html#gwy-resource-use"><code class="function">gwy_resource_use()</code></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient to get samples of.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>nsamples</code></em> :</span></p></td>
<td>A location to store the number of samples (or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>).</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Sampled <em class="parameter"><code>gradient</code></em> as a sequence of <span class="type">GdkPixbuf-like</span> RRGGBBAA
quadruplets.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-sample"></a><h3>gwy_gradient_sample ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guchar"><span class="returnvalue">guchar</span></a> * gwy_gradient_sample (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> nsamples</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guchar"><span class="type">guchar</span></a> *samples</code></em>);</pre>
<p>
Samples a gradient to an array <span class="type">GdkPixbuf-like</span> samples.
</p>
<p>
If <em class="parameter"><code>samples</code></em> is not <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>, it's resized to 4*<em class="parameter"><code>nsamples</code></em> bytes, otherwise a
new buffer is allocated.
</p>
<p>
If you don't have a reason for specific sample size (and are not going
to modify the samples or otherwise dislike the automatic resampling on
gradient definition change), use <a class="link" href="GwyGradient.html#gwy-gradient-get-samples" title="gwy_gradient_get_samples ()"><code class="function">gwy_gradient_get_samples()</code></a> instead.
This function does not need the gradient to be in use, though.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient to sample.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>nsamples</code></em> :</span></p></td>
<td>Required number of samples.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>samples</code></em> :</span></p></td>
<td>Pointer to array to be filled.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Sampled <em class="parameter"><code>gradient</code></em> as a sequence of <span class="type">GdkPixbuf-like</span> RRGGBBAA
quadruplets.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-sample-to-pixbuf"></a><h3>gwy_gradient_sample_to_pixbuf ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_sample_to_pixbuf (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/gdk-pixbuf/gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>);</pre>
<p>
Samples a color gradient to a provided pixbuf.
</p>
<p>
Unlike <a class="link" href="GwyGradient.html#gwy-gradient-sample" title="gwy_gradient_sample ()"><code class="function">gwy_gradient_sample()</code></a> which simply takes samples at equidistant
points this method uses supersampling and thus it gives a bit better
looking gradient presentation.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient to sample.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixbuf</code></em> :</span></p></td>
<td>A pixbuf to sample gradient to (in horizontal direction).</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-get-npoints"></a><h3>gwy_gradient_get_npoints ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="returnvalue">gint</span></a> gwy_gradient_get_npoints (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>);</pre>
<p>
Returns the number of points in a color gradient.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The number of points in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-get-point"></a><h3>gwy_gradient_get_point ()</h3>
<pre class="programlisting"><a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="returnvalue">GwyGradientPoint</span></a> gwy_gradient_get_point (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>);</pre>
<p>
Returns the point at given index of a color gradient.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>index_</code></em> :</span></p></td>
<td>Color point index in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Color point at <em class="parameter"><code>index_</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-set-point"></a><h3>gwy_gradient_set_point ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_set_point (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);</pre>
<p>
Sets a single color point in a color gradient.
</p>
<p>
It is an error to try to move points beyond its neighbours, or to move first
(or last) point from 0 (or 1).
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>index_</code></em> :</span></p></td>
<td>Color point index in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>point</code></em> :</span></p></td>
<td>Color point to replace current point at <em class="parameter"><code>index_</code></em> with.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-set-point-color"></a><h3>gwy_gradient_set_point_color ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_set_point_color (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="libgwydraw-GwyRGBA.html#GwyRGBA" title="GwyRGBA"><span class="type">GwyRGBA</span></a> *color</code></em>);</pre>
<p>
Sets the color of a color gradient point without moving it.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>index_</code></em> :</span></p></td>
<td>Color point index in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>color</code></em> :</span></p></td>
<td>Color to set the point to.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-insert-point"></a><h3>gwy_gradient_insert_point ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_insert_point (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);</pre>
<p>
Inserts a point to a color gradient.
</p>
<p>
It is an error to try to position a outside its future neighbours, or to
move the first (or last) point from 0 (or 1).
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>index_</code></em> :</span></p></td>
<td>Color point index in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>point</code></em> :</span></p></td>
<td>Color point to insert at <em class="parameter"><code>index_</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-insert-point-sorted"></a><h3>gwy_gradient_insert_point_sorted ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="returnvalue">gint</span></a> gwy_gradient_insert_point_sorted (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *point</code></em>);</pre>
<p>
Inserts a point into a color gradient based on its x position.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>point</code></em> :</span></p></td>
<td>Color point to insert.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The index <em class="parameter"><code>point</code></em> was inserted at.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-delete-point"></a><h3>gwy_gradient_delete_point ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_delete_point (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> index_</code></em>);</pre>
<p>
Deletes a point at given index in a color gradient.
</p>
<p>
It is not possible to delete points in gradients with less than 3 points.
First and last points should not be deleted unless there's another point
with <em class="parameter"><code>x</code></em> = 0 or <em class="parameter"><code>x</code></em> = 1 present.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>index_</code></em> :</span></p></td>
<td>Color point index in <em class="parameter"><code>gradient</code></em>.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-reset"></a><h3>gwy_gradient_reset ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_reset (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>);</pre>
<p>
Resets a gradient to the default two-point gray scale state.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-get-points"></a><h3>gwy_gradient_get_points ()</h3>
<pre class="programlisting">const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="returnvalue">GwyGradientPoint</span></a> * gwy_gradient_get_points (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> *npoints</code></em>);</pre>
<p>
Returns the complete set of color points of a gradient.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>npoints</code></em> :</span></p></td>
<td>A location to store the number of color points (or <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>).</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Complete set <em class="parameter"><code>gradient</code></em>'s color points. The returned array is
owned by <em class="parameter"><code>gradient</code></em> and must not be modified or freed.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-set-points"></a><h3>gwy_gradient_set_points ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_set_points (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> npoints</code></em>,
<em class="parameter"><code>const <a class="link" href="GwyGradient.html#GwyGradientPoint" title="GwyGradientPoint"><span class="type">GwyGradientPoint</span></a> *points</code></em>);</pre>
<p>
Sets the complete color gradient definition to a given set of points.
</p>
<p>
The point positions should be ordered, and first point should start at 0.0,
last end at 1.0. There should be no redundant points.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>npoints</code></em> :</span></p></td>
<td>The length of <em class="parameter"><code>points</code></em>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>points</code></em> :</span></p></td>
<td>Color points to set as new gradient definition.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradient-set-from-samples"></a><h3>gwy_gradient_set_from_samples ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gwy_gradient_set_from_samples (<em class="parameter"><code><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="type">GwyGradient</span></a> *gradient</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> nsamples</code></em>,
<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guchar"><span class="type">guchar</span></a> *samples</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> threshold</code></em>);</pre>
<p>
Reconstructs a color gradient definition from sampled colors.
</p>
<p>
The result is usually approximate.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>gradient</code></em> :</span></p></td>
<td>A color gradient.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>nsamples</code></em> :</span></p></td>
<td>Number of samples, it must be at least one.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>samples</code></em> :</span></p></td>
<td>Sampled color gradient in <span class="type">GdkPixbuf-like</span> RRGGBBAA form.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>threshold</code></em> :</span></p></td>
<td>Maximum allowed difference (for color components in range 0..1).
When negative, default value 1/80 suitable for most purposes
is used.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradients"></a><h3>gwy_gradients ()</h3>
<pre class="programlisting"><a href="../libgwyddion/GwyInventory.html"><span class="returnvalue">GwyInventory</span></a> * gwy_gradients (<em class="parameter"><code><span class="type">void</span></code></em>);</pre>
<p>
Gets inventory with all the gradients.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Gradient inventory.</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gwy-gradients-get-gradient"></a><h3>gwy_gradients_get_gradient ()</h3>
<pre class="programlisting"><a class="link" href="GwyGradient.html" title="GwyGradient"><span class="returnvalue">GwyGradient</span></a> * gwy_gradients_get_gradient (<em class="parameter"><code>const <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gchar"><span class="type">gchar</span></a> *name</code></em>);</pre>
<p>
Convenience function to get a gradient from <a class="link" href="GwyGradient.html#gwy-gradients" title="gwy_gradients ()"><code class="function">gwy_gradients()</code></a> by name.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>name</code></em> :</span></p></td>
<td>Gradient name. May be <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> to get the default gradient.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>Gradient identified by <em class="parameter"><code>name</code></em> or the default gradient if <em class="parameter"><code>name</code></em> does
not exist.</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<div class="refsect1">
<a name="GwyGradient.see-also"></a><h2>See Also</h2>
<a class="link" href="libgwydraw-gwypixfield.html" title="gwypixfield">gwypixfield</a> --
Drawing data with gradients,
<a href="../libgwyddion/GwyInventory.html"><span class="type">GwyInventory</span></a> -- the container holding all gradients,
<a href="../libgwydgets/GwyDataView.html"><span class="type">GwyDataView</span></a> -- 2D data display widget,
<a href="../libgwydgets/GwyColorAxis.html"><span class="type">GwyColorAxis</span></a> -- false color axis widget
</div>
</div>
<div class="footer">
<hr>
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