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* Copyright (c) 2009 Giuseppe Torelli <colossus73@gmail.com>
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License,or
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* (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not,write to the Free Software
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* Foundation,Inc.,59 Temple Place - Suite 330,Boston,MA 02111-1307,USA.
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/* This header provides us with image manipulation libraries such
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* as gdk-pixbuf and cairo. */
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/* This function is part of the mandatory API that each plug-in
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* name parameter of this function is a return location for
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* plug-in name. You must fill it with unique name, which will
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* be used to identify transition in transition type combo box. */
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void img_transition_set_name(gchar **name)
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/* This function is part of the mandatory API that each plug-in
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* This is the function that does all the transition rendering.
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* window GdkDrawable on which the final product should be drawn
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* image_from Starting pixbuf.
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* image_to End pixbuf. Both images are already scaled and transformed
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* to fit into GdkDrawable.
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* progress Value in range [0,1] which tells us how far the transition
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* is (0 means we only started transition, 1 means the
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* transition is finished).
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* file_desc File descriptor for outputting finished image (this file
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* descriptor represents the ffmpeg's stdin, on which we
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* write produced image data). If the file descriptor is < 0,
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* we should draw our produt on GtkDrawable.
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* Note: Parts enclosed in SUGGESTED comments should not be changed, since
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* most of the transitions will need them.
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void img_transition_render(GdkDrawable *window, GdkPixbuf *image_from, GdkPixbuf *image_to, gdouble progress, gint file_desc)
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cairo_surface_t *surface;
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/* With this call we obtain the dimensions of our drawing area.
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* We don't use these values in this plug-in, but this is really
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gdk_drawable_get_size(window, &width, &height);
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/* This is where we check if we need to output our product on the screen
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* or write it to the file desc. */
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cr = gdk_cairo_create(window);
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surface = cairo_image_surface_create(CAIRO_FORMAT_RGB24, width, height);
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cr = cairo_create(surface);
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/* Here we do our own drawing. In this example, we are fading image_to
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* pixbuf over the image_from pixbuf. The amount of transparency is
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* determined by the progress value (at the start of the transition,
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* image_to is fully transparent and at the end fully opaque). */
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gdk_cairo_set_source_pixbuf(cr,image_from,0,0);
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gdk_cairo_set_source_pixbuf(cr,image_to,0,0);
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cairo_paint_with_alpha(cr,progress);
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/* This function takes the burden of converting drawing product
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* to appropriate pixel data from plug-in write's shoulders. */
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img_export_cairo_to_ppm(surface, file_desc);
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cairo_surface_destroy(surface);
added
removed
transitions/cross_fade.c
