Commit 5a987c31 authored by Javier Jardón's avatar Javier Jardón

docs: migrating-2to3: Make the examples look prettier

parent 6d3b8c2c
......@@ -199,7 +199,7 @@
<title>Drawing a GdkPixbuf onto a GdkWindow</title>
<para>
Drawing a pixbuf onto a drawable used to be done like this:
<programlisting><![CDATA[
<informalexample><programlisting>
gdk_draw_pixbuf (window,
gtk_widget_get_style (widget)->black_gc,
pixbuf,
......@@ -209,14 +209,14 @@ gdk_draw_pixbuf (window,
gdk_pixbuf_get_height (pixbuf),
GDK_RGB_DITHER_NORMAL,
0, 0);
]]></programlisting>
</programlisting></informalexample>
Doing the same thing with cairo:
<programlisting><![CDATA[
<informalexample><programlisting>
cairo_t *cr = gdk_cairo_create (window);
gdk_cairo_set_source_pixbuf (cr, pixbuf, x, y);
cairo_paint (cr);
cairo_destroy (cr);
]]></programlisting>
</programlisting></informalexample>
Note that very similar code can be used for drawing pixmaps
by using gdk_cairo_set_source_pixmap() instead of
gdk_cairo_set_source_pixbuf().
......@@ -227,7 +227,7 @@ cairo_destroy (cr);
<para>
Tiled pixmaps are often used for drawing backgrounds.
Old code looked something like this:
<programlisting><![CDATA[
<informalexample><programlisting>
GdkGCValues gc_values;
GdkGC *gc;
......@@ -242,9 +242,9 @@ gdk_draw_rectangle (drawable, gc, TRUE, 0, 0, width, height);
gdk_gc_set_tile (gc, NULL);
gdk_gc_set_fill (gc, GDK_SOLID);
gdk_gc_set_ts_origin (gc, 0, 0);
]]></programlisting>
</programlisting></informalexample>
The equivalent cairo code looks like this:
<programlisting><![CDATA[
<informalexample><programlisting>
cairo_t *cr;
cr = gdk_cairo_create (drawable);
......@@ -253,7 +253,7 @@ cairo_pattern_set_extend (cairo_get_source (cr), CAIRO_EXTEND_REPEAT);
cairo_rectangle (cr, 0, 0, width, height);
cairo_fill (cr);
cairo_destroy (cr);
]]></programlisting>
</programlisting></informalexample>
Again, you can exchange pixbufs and pixmaps by using
gdk_cairo_set_source_pixbuf() instead of
gdk_cairo_set_source_pixmap().
......@@ -264,32 +264,32 @@ cairo_destroy (cr);
<para>
Drawing layouts clipped is often used to avoid overdraw or to
allow drawing selections. Code would have looked like this:
<programlisting><![CDATA[
<informalexample><programlisting>
GdkGC *gc;
/* setup */
gc = gtk_widget_get_style (widget)->text_gc[state];
gdk_gc_set_clip_rectangle (gc, &area);
gdk_gc_set_clip_rectangle (gc, &amp;area);
/* use */
gdk_draw_layout (drawable, gc, x, y, layout);
/* restore */
gdk_gc_set_clip_rectangle (gc, NULL);
]]></programlisting>
</programlisting></informalexample>
With cairo, the same effect can be achieved using:
<programlisting><![CDATA[
<informalexample><programlisting>
cairo_t *cr;
cr = gdk_cairo_create (drawable);
/* clip */
gdk_cairo_rectangle (cr, &area);
gdk_cairo_rectangle (cr, &amp;area);
cairo_clip (cr);
/* set the correct source color */
gdk_cairo_set_source_color (cr, &gtk_widget_get_style (widget)->text[state]);
gdk_cairo_set_source_color (cr, &amp;gtk_widget_get_style (widget)->text[state]);
/* draw the text */
cairo_move_to (cr, x, y);
pango_cairo_show_layout (cr, layout);
cairo_destroy (cr);
]]></programlisting>
</programlisting></informalexample>
Clipping using cairo_clip() is of course not restricted to text
rendering and can be used everywhere where GC clips were used.
And using gdk_cairo_set_source_color() with style colors should
......@@ -305,7 +305,7 @@ cairo_destroy (cr);
It was often used to achieve a checkerboard effect. You can use
cairo_mask() to achieve this effect. To get a checkerbox mask,
you can use code like this:
<programlisting><![CDATA[
<informalexample><programlisting>
static cairo_pattern_t *
gtk_color_button_get_checkered (void)
{
......@@ -326,7 +326,7 @@ gtk_color_button_get_checkered (void)
return pattern;
}
]]></programlisting>
</programlisting></informalexample>
Note that stippling looks very outdated in UIs, and is rarely
used in modern applications. All properties that made use of
stippling have been removed from GTK+ 3. Most prominently,
......@@ -340,20 +340,20 @@ gtk_color_button_get_checkered (void)
effect. Cairo does not allow this yet. You can however use
cairo_push_group() to get a different intermediate target that
you can copy to. So you can replace this code:
<programlisting><![CDATA[
<informalexample><programlisting>
gdk_draw_drawable (pixmap,
gc,
pixmap,
area.x + dx, area.y + dy,
area.x, area.y,
area.width, area.height);
]]></programlisting>
</programlisting></informalexample>
By using this code:
<programlisting><![CDATA[
<informalexample><programlisting>
cairo_t *cr = gdk_cairo_create (pixmap);
/* clipping restricts the intermediate surface's size, so it's a good idea
* to use it. */
gdk_cairo_rectangle (cr, &area);
gdk_cairo_rectangle (cr, &amp;area);
cairo_clip (cr);
/* Now push a group to change the target */
cairo_push_group (cr);
......@@ -363,7 +363,7 @@ cairo_paint (cr);
cairo_pop_group_to_source (cr);
cairo_paint (cr);
cairo_destroy (cr);
]]></programlisting>
</programlisting></informalexample>
The cairo developers plan to add self-copies in the future to allow
exactly this effect, so you might want to keep up on cairo
development to be able to change your code.
......@@ -656,7 +656,7 @@ gtk_fixed_get_preferred_height (GtkWidget *widget,
<para>
One place where pixmaps were commonly used is to create custom
cursors:
<programlisting>
<informalexample><programlisting>
GdkCursor *cursor;
GdkPixmap *pixmap;
cairo_t *cr;
......@@ -672,10 +672,10 @@ cairo_destroy (cr);
cursor = gdk_cursor_new_from_pixmap (pixmap, pixmap, &amp;fg, &amp;fg, 0, 0);
g_object_unref (pixmap);
</programlisting>
</programlisting></informalexample>
The same can be achieved without pixmaps, by drawing onto
an image surface:
<programlisting>
<informalexample><programlisting>
GdkCursor *cursor;
cairo_surface_t *s;
cairo_t *cr;
......@@ -696,7 +696,7 @@ cairo_surface_destroy (s);
cursor = gdk_cursor_new_from_pixbuf (display, pixbuf, 0, 0);
g_object_unref (pixbuf);
</programlisting>
</programlisting></informalexample>
</para>
</example>
</section>
......@@ -715,7 +715,7 @@ g_object_unref (pixbuf);
<para>You might have a screen-changed handler like the following
to set up a translucent window with an alpha-channel:
</para>
<programlisting>
<informalexample><programlisting>
static void
on_alpha_screen_changed (GtkWidget *widget,
GdkScreen *old_screen,
......@@ -729,11 +729,11 @@ on_alpha_screen_changed (GtkWidget *widget,
gtk_widget_set_colormap (widget, colormap);
}
</programlisting>
</programlisting></informalexample>
<para>
With visuals instead of colormaps, this will look as follows:
</para>
<programlisting>
<informalexample><programlisting>
static void
on_alpha_screen_changed (GtkWindow *window,
GdkScreen *old_screen,
......@@ -747,7 +747,7 @@ on_alpha_screen_changed (GtkWindow *window,
gtk_widget_set_visual (window, visual);
}
</programlisting>
</programlisting></informalexample>
</example>
</section>
......
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