diff options
Diffstat (limited to 'trunk/pango/pango-matrix.c')
| -rw-r--r-- | trunk/pango/pango-matrix.c | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/trunk/pango/pango-matrix.c b/trunk/pango/pango-matrix.c new file mode 100644 index 00000000..828d4f90 --- /dev/null +++ b/trunk/pango/pango-matrix.c @@ -0,0 +1,467 @@ +/* Pango + * pango-matrix.c: Matrix manipulation routines + * + * Copyright (C) 2000, 2006 Red Hat Software + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 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 Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include <config.h> +#include <stdlib.h> +#include <math.h> + +#include "pango-matrix.h" +#include "pango-impl-utils.h" + +GType +pango_matrix_get_type (void) +{ + static GType our_type = 0; + + if (G_UNLIKELY (our_type == 0)) + our_type = g_boxed_type_register_static (I_("PangoMatrix"), + (GBoxedCopyFunc) pango_matrix_copy, + (GBoxedFreeFunc) pango_matrix_free); + + return our_type; +} + +/** + * pango_matrix_copy: + * @matrix: a #PangoMatrix, can be %NULL + * + * Copies a #PangoMatrix. + * + * Return value: the newly allocated #PangoMatrix, which should + * be freed with pango_matrix_free(), or %NULL if + * @matrix was %NULL. + * + * Since: 1.6 + **/ +PangoMatrix * +pango_matrix_copy (const PangoMatrix *matrix) +{ + PangoMatrix *new_matrix; + + if (matrix) + { + new_matrix = g_slice_new (PangoMatrix); + *new_matrix = *matrix; + } + else + new_matrix = NULL; + + return new_matrix; +} + +/** + * pango_matrix_free: + * @matrix: a #PangoMatrix, or %NULL + * + * Free a #PangoMatrix created with pango_matrix_copy(). + * Does nothing if @matrix is %NULL. + * + * Since: 1.6 + **/ +void +pango_matrix_free (PangoMatrix *matrix) +{ + if (matrix) + g_slice_free (PangoMatrix, matrix); +} + +/** + * pango_matrix_translate: + * @matrix: a #PangoMatrix + * @tx: amount to translate in the X direction + * @ty: amount to translate in the Y direction + * + * Changes the transformation represented by @matrix to be the + * transformation given by first translating by (@tx, @ty) + * then applying the original transformation. + * + * Since: 1.6 + **/ +void +pango_matrix_translate (PangoMatrix *matrix, + double tx, + double ty) +{ + g_return_if_fail (matrix != NULL); + + matrix->x0 = matrix->xx * tx + matrix->xy * ty + matrix->x0; + matrix->y0 = matrix->yx * tx + matrix->yy * ty + matrix->y0; +} + +/** + * pango_matrix_scale: + * @matrix: a #PangoMatrix + * @scale_x: amount to scale by in X direction + * @scale_y: amount to scale by in Y direction + * + * Changes the transformation represented by @matrix to be the + * transformation given by first scaling by @sx in the X direction + * and @sy in the Y direction then applying the original + * transformation. + * + * Since: 1.6 + **/ +void +pango_matrix_scale (PangoMatrix *matrix, + double scale_x, + double scale_y) +{ + g_return_if_fail (matrix != NULL); + + matrix->xx *= scale_x; + matrix->xy *= scale_y; + matrix->yx *= scale_x; + matrix->yy *= scale_y; +} + +/** + * pango_matrix_rotate: + * @matrix: a #PangoMatrix + * @degrees: degrees to rotate counter-clockwise + * + * Changes the transformation represented by @matrix to be the + * transformation given by first rotating by @degrees degrees + * counter-clockwise then applying the original transformation. + * + * Since: 1.6 + **/ +void +pango_matrix_rotate (PangoMatrix *matrix, + double degrees) +{ + PangoMatrix tmp; + gdouble r, s, c; + + g_return_if_fail (matrix != NULL); + + r = degrees * (G_PI / 180.); + s = sin (r); + c = cos (r); + + tmp.xx = c; + tmp.xy = s; + tmp.yx = -s; + tmp.yy = c; + tmp.x0 = 0; + tmp.y0 = 0; + + pango_matrix_concat (matrix, &tmp); +} + +/** + * pango_matrix_concat: + * @matrix: a #PangoMatrix + * @new_matrix: a #PangoMatrix + * + * Changes the transformation represented by @matrix to be the + * transformation given by first applying transformation + * given by @new_matrix then applying the original transformation. + * + * Since: 1.6 + **/ +void +pango_matrix_concat (PangoMatrix *matrix, + const PangoMatrix *new_matrix) +{ + PangoMatrix tmp; + + g_return_if_fail (matrix != NULL); + + tmp = *matrix; + + matrix->xx = tmp.xx * new_matrix->xx + tmp.xy * new_matrix->yx; + matrix->xy = tmp.xx * new_matrix->xy + tmp.xy * new_matrix->yy; + matrix->yx = tmp.yx * new_matrix->xx + tmp.yy * new_matrix->yx; + matrix->yy = tmp.yx * new_matrix->xy + tmp.yy * new_matrix->yy; + matrix->x0 = tmp.xx * new_matrix->x0 + tmp.xy * new_matrix->y0 + tmp.x0; + matrix->y0 = tmp.yx * new_matrix->y0 + tmp.yy * new_matrix->y0 + tmp.y0; +} + +/** + * pango_matrix_get_font_scale_factor: + * @matrix: a #PangoMatrix, may be %NULL + * + * Returns the scale factor of a matrix on the height of the font. + * That is, the scale factor in the direction perpendicular to the + * vector that the X coordinate is mapped to. + * + * Return value: the scale factor of @matrix on the height of the font, + * or 1.0 if @matrix is %NULL. + * + * Since: 1.12 + **/ +double +pango_matrix_get_font_scale_factor (const PangoMatrix *matrix) +{ +/* + * Based on cairo-matrix.c:_cairo_matrix_compute_scale_factors() + * + * Copyright 2005, Keith Packard + */ + double det; + + if (!matrix) + return 1.0; + + det = matrix->xx * matrix->yy - matrix->yx * matrix->xy; + + if (det == 0) + { + return 0.0; + } + else + { + double x = matrix->xx; + double y = matrix->yx; + double major, minor; + + major = sqrt (x*x + y*y); + + /* + * ignore mirroring + */ + if (det < 0) + det = - det; + + if (major) + minor = det / major; + else + minor = 0.0; + + return minor; + } +} + +/** + * pango_matrix_transform_distance: + * @matrix: a #PangoMatrix, or %NULL + * @dx: in/out X component of a distance vector + * @dy: yn/out Y component of a distance vector + * + * Transforms the distance vector (@dx,@dy) by @matrix. This is + * similar to pango_matrix_transform_point() except that the translation + * components of the transformation are ignored. The calculation of + * the returned vector is as follows: + * + * <programlisting> + * dx2 = dx1 * xx + dy1 * xy; + * dy2 = dx1 * yx + dy1 * yy; + * </programlisting> + * + * Affine transformations are position invariant, so the same vector + * always transforms to the same vector. If (@x1,@y1) transforms + * to (@x2,@y2) then (@x1+@dx1,@y1+@dy1) will transform to + * (@x1+@dx2,@y1+@dy2) for all values of @x1 and @x2. + * + * Since: 1.16 + **/ +void +pango_matrix_transform_distance (const PangoMatrix *matrix, + double *dx, + double *dy) +{ + if (matrix) + { + double new_x, new_y; + + new_x = (matrix->xx * *dx + matrix->xy * *dy); + new_y = (matrix->yx * *dx + matrix->yy * *dy); + + *dx = new_x; + *dy = new_y; + } +} + +/** + * pango_matrix_transform_point: + * @matrix: a #PangoMatrix, or %NULL + * @x: in/out X position + * @y: in/out Y position + * + * Transforms the point (@x, @y) by @matrix. + * + * Since: 1.16 + **/ +void +pango_matrix_transform_point (const PangoMatrix *matrix, + double *x, + double *y) +{ + if (matrix) + { + pango_matrix_transform_distance (matrix, x, y); + + *x += matrix->x0; + *y += matrix->y0; + } +} + +/** + * pango_matrix_transform_rectangle: + * @matrix: a #PangoMatrix, or %NULL + * @rect: in/out bounding box in Pango units, or %NULL + * + * First transforms @rect using @matrix, then calculates the bounding box + * of the transformed rectangle. The rectangle should be in Pango units. + * + * This function is useful for example when you want to draw a rotated + * @PangoLayout to an image buffer, and want to know how large the image + * should be and how much you should shift the layout when rendering. + * + * If you have a rectangle in device units (pixels), use + * pango_matrix_transform_pixel_rectangle(). + * + * If you have the rectangle in Pango units and want to convert to + * transformed pixel bounding box, it is more accurate to transform it first + * (using this function) and pass the result to pango_extents_to_pixels(), + * as @ink_rect. However, there is a reason that you may want to convert + * to pixels first and then transform, and that is when the transformed + * coordinates may overflow in Pango units (large matrix translation for + * example). + * + * Since: 1.16 + **/ +void +pango_matrix_transform_rectangle (const PangoMatrix *matrix, + PangoRectangle *rect) +{ + int i; + double quad_x[4], quad_y[4]; + double dx1, dy1; + double dx2, dy2; + double min_x, max_x; + double min_y, max_y; + + if (!rect || !matrix) + return; + + quad_x[0] = pango_units_to_double (rect->x); + quad_y[0] = pango_units_to_double (rect->y); + pango_matrix_transform_point (matrix, &quad_x[0], &quad_y[0]); + + dx1 = pango_units_to_double (rect->width); + dy1 = 0; + pango_matrix_transform_distance (matrix, &dx1, &dy1); + quad_x[1] = quad_x[0] + dx1; + quad_y[1] = quad_y[0] + dy1; + + dx2 = 0; + dy2 = pango_units_to_double (rect->height); + pango_matrix_transform_distance (matrix, &dx2, &dy2); + quad_x[2] = quad_x[0] + dx2; + quad_y[2] = quad_y[0] + dy2; + + quad_x[3] = quad_x[0] + dx1 + dx2; + quad_y[3] = quad_y[0] + dy1 + dy2; + + min_x = max_x = quad_x[0]; + min_y = max_y = quad_y[0]; + + for (i=1; i < 4; i++) { + if (quad_x[i] < min_x) + min_x = quad_x[i]; + else if (quad_x[i] > max_x) + max_x = quad_x[i]; + + if (quad_y[i] < min_y) + min_y = quad_y[i]; + else if (quad_y[i] > max_y) + max_y = quad_y[i]; + } + + rect->x = pango_units_from_double (min_x); + rect->y = pango_units_from_double (min_y); + rect->width = pango_units_from_double (max_x) - rect->x; + rect->height = pango_units_from_double (max_y) - rect->y; +} + +/** + * pango_matrix_transform_pixel_rectangle: + * @matrix: a #PangoMatrix, or %NULL + * @rect: in/out bounding box in device units, or %NULL + * + * First transforms the @rect using @matrix, then calculates the bounding box + * of the transformed rectangle. The rectangle should be in device units + * (pixels). + * + * This function is useful for example when you want to draw a rotated + * @PangoLayout to an image buffer, and want to know how large the image + * should be and how much you should shift the layout when rendering. + * + * For better accuracy, you should use pango_matrix_transform_rectangle() on + * original rectangle in Pango units and convert to pixels afterward + * using pango_extents_to_pixels() as @ink_rect. + * + * Since: 1.16 + **/ +void +pango_matrix_transform_pixel_rectangle (const PangoMatrix *matrix, + PangoRectangle *rect) +{ + int i; + double quad_x[4], quad_y[4]; + double dx1, dy1; + double dx2, dy2; + double min_x, max_x; + double min_y, max_y; + + if (!rect || !matrix) + return; + + quad_x[0] = rect->x; + quad_y[0] = rect->y; + pango_matrix_transform_point (matrix, &quad_x[0], &quad_y[0]); + + dx1 = rect->width; + dy1 = 0; + pango_matrix_transform_distance (matrix, &dx1, &dy1); + quad_x[1] = quad_x[0] + dx1; + quad_y[1] = quad_y[0] + dy1; + + dx2 = 0; + dy2 = rect->height; + pango_matrix_transform_distance (matrix, &dx2, &dy2); + quad_x[2] = quad_x[0] + dx2; + quad_y[2] = quad_y[0] + dy2; + + quad_x[3] = quad_x[0] + dx1 + dx2; + quad_y[3] = quad_y[0] + dy1 + dy2; + + min_x = max_x = quad_x[0]; + min_y = max_y = quad_y[0]; + + for (i=1; i < 4; i++) { + if (quad_x[i] < min_x) + min_x = quad_x[i]; + else if (quad_x[i] > max_x) + max_x = quad_x[i]; + + if (quad_y[i] < min_y) + min_y = quad_y[i]; + else if (quad_y[i] > max_y) + max_y = quad_y[i]; + } + + rect->x = min_x; + rect->y = min_y; + rect->width = max_x - rect->x; + rect->height = max_y - rect->y; +} |