PIKApp/libpika/pikagradientchooser.c

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2023-10-30 23:56:43 +01:00
/* LIBPIKA - The PIKA Library
* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
*
* pikagradientchooser.c
* Copyright (C) 1998 Andy Thomas
*
* This library is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <gegl.h>
#include <gtk/gtk.h>
#include "libpikawidgets/pikawidgets.h"
#include "pika.h"
#include "pikauitypes.h"
#include "pikagradientchooser.h"
#include "pikauimarshal.h"
#include "libpika-intl.h"
/**
* SECTION: pikagradientchooser
* @title: PikaGradientChooser
* @short_description: A button which pops up a gradient select dialog.
*
* A button which pops up a gradient select dialog.
**/
struct _PikaGradientChooser
{
PikaResourceChooser parent_instance;
GtkWidget *preview;
};
/* local function prototypes */
static void pika_gradient_chooser_draw_interior (PikaResourceChooser *self);
static void pika_gradient_select_preview_size_allocate (GtkWidget *widget,
GtkAllocation *allocation,
PikaGradientChooser *self);
static gboolean pika_gradient_select_preview_draw_handler (GtkWidget *preview,
cairo_t *cr,
PikaGradientChooser *self);
static const GtkTargetEntry drag_target = { "application/x-pika-gradient-name", 0 };
G_DEFINE_FINAL_TYPE (PikaGradientChooser,
pika_gradient_chooser,
PIKA_TYPE_RESOURCE_CHOOSER)
/* Initial dimensions of widget. */
#define CELL_HEIGHT 18
#define CELL_WIDTH 84
static void
pika_gradient_chooser_class_init (PikaGradientChooserClass *klass)
{
PikaResourceChooserClass *superclass = PIKA_RESOURCE_CHOOSER_CLASS (klass);
superclass->draw_interior = pika_gradient_chooser_draw_interior;
superclass->resource_type = PIKA_TYPE_GRADIENT;
}
static void
pika_gradient_chooser_init (PikaGradientChooser *self)
{
GtkWidget *button;
button = gtk_button_new ();
gtk_container_add (GTK_CONTAINER (self), button);
self->preview = gtk_drawing_area_new ();
gtk_widget_set_size_request (self->preview, CELL_WIDTH, CELL_HEIGHT);
gtk_container_add (GTK_CONTAINER (button), self->preview);
g_signal_connect (self->preview, "size-allocate",
G_CALLBACK (pika_gradient_select_preview_size_allocate),
self);
g_signal_connect (self->preview, "draw",
G_CALLBACK (pika_gradient_select_preview_draw_handler),
self);
gtk_widget_show_all (GTK_WIDGET (self));
pika_resource_chooser_set_drag_target (PIKA_RESOURCE_CHOOSER (self),
self->preview, &drag_target);
pika_resource_chooser_set_clickable (PIKA_RESOURCE_CHOOSER (self), button);
}
static void
pika_gradient_chooser_draw_interior (PikaResourceChooser *self)
{
PikaGradientChooser *gradient_select = PIKA_GRADIENT_CHOOSER (self);
gtk_widget_queue_draw (gradient_select->preview);
}
/**
* pika_gradient_chooser_new:
* @title: (nullable): Title of the dialog to use or %NULL to use the default title.
* @label: (nullable): Button label or %NULL for no label.
* @gradient: (nullable): Initial gradient.
*
* Creates a new #GtkWidget that lets a user choose a gradient.
* You can use this widget in a table in a plug-in dialog.
*
* Returns: A #GtkWidget that you can use in your UI.
*
* Since: 2.4
*/
GtkWidget *
pika_gradient_chooser_new (const gchar *title,
const gchar *label,
PikaResource *gradient)
{
GtkWidget *self;
if (gradient == NULL)
gradient = PIKA_RESOURCE (pika_context_get_gradient ());
if (title)
self = g_object_new (PIKA_TYPE_GRADIENT_CHOOSER,
"title", title,
"label", label,
"resource", gradient,
NULL);
else
self = g_object_new (PIKA_TYPE_GRADIENT_CHOOSER,
"label", label,
"resource", gradient,
NULL);
pika_gradient_chooser_draw_interior (PIKA_RESOURCE_CHOOSER (self));
return self;
}
/* private functions */
/* Get array of samples from self's gradient.
* Return array and size at given handles.
* Return success.
*/
static gboolean
get_gradient_data (PikaGradientChooser *self,
gint allocation_width,
gint *sample_count,
gdouble **sample_array)
{
PikaGradient *gradient;
gboolean result;
gdouble *samples;
gint n_samples;
g_object_get (self, "resource", &gradient, NULL);
result = pika_gradient_get_uniform_samples (gradient,
allocation_width,
FALSE, /* not reversed. */
&n_samples,
&samples);
if (result)
{
/* Return array of samples to dereferenced handles. */
*sample_array = samples;
*sample_count = n_samples;
}
g_object_unref (gradient);
/* When result is true, caller must free the array. */
return result;
}
/* Called on widget resized. */
static void
pika_gradient_select_preview_size_allocate (GtkWidget *widget,
GtkAllocation *allocation,
PikaGradientChooser *self)
{
/* Do nothing.
*
* In former code, we cached the gradient data in self, on allocate event.
* But allocate event always seems to be paired with a draw event,
* so there is no point in caching the gradient data.
* And caching gradient data is a premature optimization,
* without deep knowledge of Gtk and actual performance testing,
* you can't know caching helps performance.
*/
}
/* Draw array of samples.
* This understands mostly cairo, and little about gradient.
*/
static void
pika_gradient_select_preview_draw (cairo_t *cr,
gint src_width,
gint dest_width,
gdouble *src)
{
cairo_pattern_t *pattern;
cairo_surface_t *surface;
guchar *dest;
gint x;
pattern = pika_cairo_checkerboard_create (cr, PIKA_CHECK_SIZE_SM, NULL, NULL);
cairo_set_source (cr, pattern);
cairo_pattern_destroy (pattern);
cairo_paint (cr);
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, src_width, 1);
for (x = 0, dest = cairo_image_surface_get_data (surface);
x < src_width;
x++, src += 4, dest += 4)
{
PikaRGB color;
guchar r, g, b, a;
pika_rgba_set (&color, src[0], src[1], src[2], src[3]);
pika_rgba_get_uchar (&color, &r, &g, &b, &a);
PIKA_CAIRO_ARGB32_SET_PIXEL (dest, r, g, b, a);
}
cairo_surface_mark_dirty (surface);
pattern = cairo_pattern_create_for_surface (surface);
cairo_pattern_set_extend (pattern, CAIRO_EXTEND_REFLECT);
cairo_surface_destroy (surface);
cairo_scale (cr, (gdouble) dest_width / (gdouble) src_width, 1.0);
cairo_set_source (cr, pattern);
cairo_pattern_destroy (pattern);
cairo_paint (cr);
}
/* Handles a draw signal.
* Draw self, i.e. interior of button.
*
* Always returns FALSE, but doesn't draw when fail to get gradient data.
*
* Is passed neither gradient nor attributes of gradient: get them now from self.
*/
static gboolean
pika_gradient_select_preview_draw_handler (GtkWidget *widget,
cairo_t *cr,
PikaGradientChooser *self)
{
GtkAllocation allocation;
/* Attributes of the source.*/
gdouble *src;
gint n_samples;
gint src_width;
gtk_widget_get_allocation (widget, &allocation);
if (!get_gradient_data (self, allocation.width, &n_samples, &src))
return FALSE;
/* Width in pixels of src, since BPP is 4. */
src_width = n_samples / 4;
pika_gradient_select_preview_draw (cr, src_width, allocation.width, src);
g_free (src);
return FALSE;
}