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/* Eye of Mate image viewer - utility functions for computing zoom factors
*
* Copyright (C) 2000 The Free Software Foundation
*
* Author: Federico Mena-Quintero <federico@gnu.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <config.h>
#include <math.h>
#include "zoom.h"
/**
* zoom_fit_size:
* @dest_width: Width of destination area.
* @dest_height: Height of destination area.
* @src_width: Width of source image.
* @src_height: Height of source image.
* @upscale_smaller: Whether to scale up images smaller than the destination size.
* @width: Return value for image width.
* @height: Return value for image height.
*
* Computes the final dimensions of an image that is to be scaled to fit to a
* certain size. If @upscale_smaller is TRUE, then images smaller than the
* destination size will be scaled up; otherwise, they will be left at their
* original size.
**/
void
zoom_fit_size (guint dest_width, guint dest_height,
guint src_width, guint src_height,
gboolean upscale_smaller,
guint *width, guint *height)
{
guint w, h;
g_return_if_fail (width != NULL);
g_return_if_fail (height != NULL);
if (src_width == 0 || src_height == 0) {
*width = 0;
*height = 0;
return;
}
if (src_width <= dest_width && src_height <= dest_height && !upscale_smaller) {
*width = src_width;
*height = src_height;
return;
}
w = dest_width;
h = floor ((double) (src_height * w) / src_width + 0.5);
if (h > dest_height) {
h = dest_height;
w = floor ((double) (src_width * h) / src_height + 0.5);
}
g_assert (w <= dest_width);
g_assert (h <= dest_height);
*width = w;
*height = h;
}
/**
* zoom_fit_scale:
* @dest_width: Width of destination area.
* @dest_height: Height of destination area.
* @src_width: Width of source image.
* @src_height: Height of source image.
* @upscale_smaller: Whether to scale up images smaller than the destination size.
*
* Similar to zoom_fit_size(), but returns the zoom factor of the final image
* with respect to the original image's size.
*
* Return value: Zoom factor with respect to the original size.
**/
double
zoom_fit_scale (guint dest_width, guint dest_height,
guint src_width, guint src_height,
gboolean upscale_smaller)
{
guint w, h;
double wfactor, hfactor;
double factor;
if (src_width == 0 || src_height == 0)
return 1.0;
if (dest_width == 0 || dest_height == 0)
return 0.0;
zoom_fit_size (dest_width, dest_height, src_width, src_height, upscale_smaller, &w, &h);
wfactor = (double) w / src_width;
hfactor = (double) h / src_height;
factor = MIN (wfactor, hfactor);
return factor;
}
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