1 files changed, 118 insertions, 0 deletions
diff --git a/src/zoom.c b/src/zoom.c
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index 0000000..aa027de
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+++ b/src/zoom.c
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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 <[email protected]>
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307, 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;
+}
+