Second commit

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 172 insertions, 0 deletions

diff --git a/transform.c b/transform.c
new file mode 100644
index 0000000..b9461d7
--- /dev/null
+++ b/transform.c
@@ -0,0 +1,172 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+enum transformation trans = TRANS_NONE;
+
+static GdkPixbuf *
+make_negative(GdkPixbuf *image)
+{
+	GdkPixbuf *new_image;
+	uint8_t *pixels;
+	int width, height, rowstride, channels, x, y;
+
+	new_image = gdk_pixbuf_copy(image);
+	if (!new_image)
+		exit(1);
+
+	pixels    = gdk_pixbuf_get_pixels(new_image);
+	width     = gdk_pixbuf_get_width(new_image);
+	height    = gdk_pixbuf_get_height(new_image);
+	rowstride = gdk_pixbuf_get_rowstride(new_image);
+	channels  = gdk_pixbuf_get_n_channels(new_image);
+
+	for (y = 0; y < height; y++) {
+		for (x = 0; x < width * channels; x += channels) {
+			/* TODO
+			 *    use libcolour to convert to CIE LChuv
+			 *    (or CIE LChab which isn't supported yet),
+			 *    then invert the lightness and the hue
+			 *    and then convert back to sRGB; however
+			 *    we must account for the fact that some
+			 *    pixels may be out of gamut
+			 *
+			 * TODO
+			 *    this may be a bit slow, so we to use
+			 *    opencl if available and otherwise use
+			 *    libcolour_convert_en_masse as much as
+			 *    possible and cache the negative for
+			 *    each file
+			 *
+			 * TODO
+			 *    it shall be a configuration in Prefernces
+			 *    what model is used for colour inversion
+			 */
+			pixels[x + 0] = 255 - pixels[x + 0];
+			pixels[x + 1] = 255 - pixels[x + 1];
+			pixels[x + 2] = 255 - pixels[x + 2];
+		}
+		pixels = &pixels[rowstride];
+	}
+
+	return new_image;
+}
+
+static GdkPixbuf *
+apply_rotation_and_reflection(GdkPixbuf *image)
+{
+	GdkPixbuf *new_image, *newer_image;
+
+	switch (trans & 7u) {
+	case TRANS_NONE:
+		return NULL;
+	case TRANS_CLOCKWISE:
+		new_image = gdk_pixbuf_rotate_simple(image, GDK_PIXBUF_ROTATE_CLOCKWISE);
+		break;
+	case TRANS_180_DEGREES:
+		new_image = gdk_pixbuf_rotate_simple(image, GDK_PIXBUF_ROTATE_UPSIDEDOWN);
+		break;
+	case TRANS_ANTICLOCKWISE:
+		new_image = gdk_pixbuf_rotate_simple(image, GDK_PIXBUF_ROTATE_COUNTERCLOCKWISE);
+		break;
+	case TRANS_FLIP:
+	case TRANS_TRANSPOSE:
+		new_image = gdk_pixbuf_flip(image, 0);
+		break;
+	case TRANS_FLOP:
+	case TRANS_ANTITRANSPOSE:
+		new_image = gdk_pixbuf_flip(image, 1);
+		break;
+	}
+	if (!new_image)
+		exit(1);
+
+	switch (trans & 7u) {
+	case TRANS_TRANSPOSE:
+	case TRANS_ANTITRANSPOSE:
+		newer_image = gdk_pixbuf_rotate_simple(new_image, GDK_PIXBUF_ROTATE_CLOCKWISE);
+		if (!newer_image)
+			exit(1);
+		g_object_unref(new_image);
+		return newer_image;
+	default:
+		return new_image;
+	}
+}
+
+GdkPixbuf *
+apply_transformations(GdkPixbuf *image)
+{
+	GdkPixbuf *negative_image, *new_image;
+	negative_image = (trans & TRANS_NEGATIVE) ? make_negative(image) : NULL;
+	new_image = apply_rotation_and_reflection(negative_image ? negative_image : image);
+	if (!new_image)
+		new_image = negative_image ? negative_image : image;
+	else if (negative_image)
+		g_object_unref(negative_image);
+	return new_image == image ? NULL : new_image;
+}
+
+static enum transformation
+inverse_transformation(enum transformation t)
+{
+	return ((4u - t) & 3u) | (t & ~3u);
+}
+
+enum transformation
+reset_transformations_without_redraw(void)
+{
+	enum transformation augment = inverse_transformation(trans & 7u);
+	trans &= ~7u;
+	return augment;
+}
+
+int
+add_transformation_without_redraw(enum transformation augment)
+{
+	enum transformation old = trans;
+	if (augment & TRANS_TRANSPOSE)
+		trans = ((augment - trans) & 3u) | ((augment ^ trans) & ~3u);
+	else
+		trans = ((augment + trans) & 3u) | ((augment ^ trans) & ~3u);
+	return trans != old;
+}
+
+void
+transform_point(enum transformation t, double *x, double *y, double *w, double *h)
+{
+	double x1 = *x, y1 = *y, x2 = *w, y2 = *h;
+
+	switch (t & 7u) {
+	case TRANS_NONE:
+		return;
+	case TRANS_CLOCKWISE:
+		*x = y2 - y1;
+		*y = x1;
+		break;
+	case TRANS_180_DEGREES:
+		*x = x2 - x1;
+		*y = y2 - y1;
+		return;
+	case TRANS_ANTICLOCKWISE:
+		*x = y1;
+		*y = x2 - x1;
+		break;
+	case TRANS_TRANSPOSE:
+		*x = y1;
+		*y = x1;
+		break;
+	case TRANS_FLIP:
+		*y = y2 - y1;
+		return;
+	case TRANS_ANTITRANSPOSE:
+		*x = y2 - y1;
+		*y = x2 - x1;
+		break;
+	case TRANS_FLOP:
+		*x = x2 - x1;
+		return;
+	}
+
+	*w = y2;
+	*h = x2;
+}