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gimp/app/display/gimpdisplayshell-transform.c

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/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* 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 <gtk/gtk.h>
#include "display-types.h"
#include "core/gimpdrawable.h"
#include "core/gimpimage.h"
#include "gimpdisplay.h"
#include "gimpdisplayshell.h"
#include "gimpdisplayshell-transform.h"
/**
* gimp_display_shell_transform_coords:
* @shell: a #GimpDisplayShell
* @image_coords: image coordinates
* @display_coords: returns the corresponding display coordinates
*
* Transforms from image coordinates to display coordinates, so that
* objects can be rendered at the correct points on the display.
**/
void
gimp_display_shell_transform_coords (GimpDisplayShell *shell,
GimpCoords *image_coords,
GimpCoords *display_coords)
{
gdouble scalex;
gdouble scaley;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (image_coords != NULL);
g_return_if_fail (display_coords != NULL);
*display_coords = *image_coords;
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
display_coords->x = scalex * image_coords->x;
display_coords->y = scaley * image_coords->y;
display_coords->x += - shell->offset_x + shell->disp_xoffset;
display_coords->y += - shell->offset_y + shell->disp_yoffset;
}
/**
* gimp_display_shell_untransform_coords:
* @shell: a #GimpDisplayShell
* @display_coords: display coordinates
* @image_coords: returns the corresonding image coordinates
*
* Transforms from display coordinates to image coordinates, so that
* points on the display can be mapped to points in the image.
**/
void
gimp_display_shell_untransform_coords (GimpDisplayShell *shell,
GimpCoords *display_coords,
GimpCoords *image_coords)
{
gdouble scalex;
gdouble scaley;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (display_coords != NULL);
g_return_if_fail (image_coords != NULL);
*image_coords = *display_coords;
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
image_coords->x = display_coords->x - shell->disp_xoffset + shell->offset_x;
image_coords->y = display_coords->y - shell->disp_yoffset + shell->offset_y;
image_coords->x /= scalex;
image_coords->y /= scaley;
}
/**
* gimp_display_shell_transform_xy:
* @shell: a #GimpDisplayShell
* @x: x coordinate of point in image coordinates
* @y: y coordinate of point in image coordinate
* @nx: returns the transformed x coordinate
* @ny: returns the transformed y coordinate
* @use_offsets: if %TRUE, the @x and @y coordinates are in the coordinate
* system of the active drawable instead of the image
*
* Transforms from image coordinates to display coordinates, so that objects
* can be rendered at the correct points on the display.
**/
void
gimp_display_shell_transform_xy (GimpDisplayShell *shell,
gdouble x,
gdouble y,
gint *nx,
gint *ny,
gboolean use_offsets)
{
gdouble scalex;
gdouble scaley;
gint offset_x = 0;
gint offset_y = 0;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (nx != NULL);
g_return_if_fail (ny != NULL);
/* transform from image coordinates to screen coordinates */
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
if (use_offsets)
gimp_item_offsets (GIMP_ITEM (gimp_image_active_drawable (shell->display->image)),
&offset_x, &offset_y);
x = (scalex * (x + offset_x) - shell->offset_x);
y = (scaley * (y + offset_y) - shell->offset_y);
/* The projected coordinates can easily overflow a gint in the case of big
images at high zoom levels, so we clamp them here to avoid problems. */
x = CLAMP (x, G_MININT, G_MAXINT);
y = CLAMP (y, G_MININT, G_MAXINT);
*nx = PROJ_ROUND (x) + shell->disp_xoffset;
*ny = PROJ_ROUND (y) + shell->disp_yoffset;
}
/**
* gimp_display_shell_untransform_xy:
* @shell: a #GimpDisplayShell
* @x: x coordinate in display coordinates
* @y: y coordinate in display coordinates
* @nx: returns x oordinate in image coordinates
* @ny: returns y coordinate in image coordinates
* @round: if %TRUE, round the results to the nearest integer;
* if %FALSE, simply cast them to @gint.
* @use_offsets: if %TRUE, @nx and @ny will be returned in the coordinate
* system of the active drawable instead of the image
*
* Transform from display coordinates to image coordinates, so that
* points on the display can be mapped to the corresponding points
* in the image.
**/
void
gimp_display_shell_untransform_xy (GimpDisplayShell *shell,
gint x,
gint y,
gint *nx,
gint *ny,
gboolean round,
gboolean use_offsets)
{
gdouble scalex;
gdouble scaley;
gint offset_x = 0;
gint offset_y = 0;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (nx != NULL);
g_return_if_fail (ny != NULL);
x -= shell->disp_xoffset;
y -= shell->disp_yoffset;
/* transform from screen coordinates to image coordinates */
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
if (use_offsets)
gimp_item_offsets (GIMP_ITEM (gimp_image_active_drawable (shell->display->image)),
&offset_x, &offset_y);
if (round)
{
*nx = ROUND ((x + shell->offset_x) / scalex - offset_x);
*ny = ROUND ((y + shell->offset_y) / scaley - offset_y);
}
else
{
*nx = (gint) ((x + shell->offset_x) / scalex - offset_x);
*ny = (gint) ((y + shell->offset_y) / scaley - offset_y);
}
}
/**
* gimp_display_shell_transform_xy_f:
* @shell: a #GimpDisplayShell
* @x: x coordinate of point in image coordinates
* @y: y coordinate of point in image coordinate
* @nx: returns the transformed x coordinate
* @ny: returns the transformed y coordinate
* @use_offsets: if %TRUE, the @x and @y coordinates are in the coordinate
* system of the active drawable instead of the image
*
* This function is identical to gimp_display_shell_transfrom_xy(),
* except that it returns its results as doubles rather than ints.
**/
void
gimp_display_shell_transform_xy_f (GimpDisplayShell *shell,
gdouble x,
gdouble y,
gdouble *nx,
gdouble *ny,
gboolean use_offsets)
{
gdouble scalex;
gdouble scaley;
gint offset_x = 0;
gint offset_y = 0;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (nx != NULL);
g_return_if_fail (ny != NULL);
/* transform from gimp coordinates to screen coordinates */
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
if (use_offsets)
gimp_item_offsets (GIMP_ITEM (gimp_image_active_drawable (shell->display->image)),
&offset_x, &offset_y);
*nx = scalex * (x + offset_x) - shell->offset_x;
*ny = scaley * (y + offset_y) - shell->offset_y;
*nx += shell->disp_xoffset;
*ny += shell->disp_yoffset;
}
/**
* gimp_display_shell_untransform_xy_f:
* @shell: a #GimpDisplayShell
* @x: x coordinate in display coordinates
* @y: y coordinate in display coordinates
* @nx: place to return x coordinate in image coordinates
* @ny: place to return y coordinate in image coordinates
* @use_offsets: if %TRUE, @nx and @ny will be returned in the coordinate
* system of the active drawable instead of the image
*
* This function is identical to gimp_display_shell_untransform_xy(),
* except that the input and output coordinates are doubles rather than
* ints, and consequently there is no option related to rounding.
**/
void
gimp_display_shell_untransform_xy_f (GimpDisplayShell *shell,
gdouble x,
gdouble y,
gdouble *nx,
gdouble *ny,
gboolean use_offsets)
{
gdouble scalex;
gdouble scaley;
gint offset_x = 0;
gint offset_y = 0;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
g_return_if_fail (nx != NULL);
g_return_if_fail (ny != NULL);
x -= shell->disp_xoffset;
y -= shell->disp_yoffset;
/* transform from screen coordinates to gimp coordinates */
scalex = SCALEFACTOR_X (shell);
scaley = SCALEFACTOR_Y (shell);
if (use_offsets)
gimp_item_offsets (GIMP_ITEM (gimp_image_active_drawable (shell->display->image)),
&offset_x, &offset_y);
*nx = (x + shell->offset_x) / scalex - offset_x;
*ny = (y + shell->offset_y) / scaley - offset_y;
}
/**
* gimp_display_shell_untransform_viewport:
* @shell: a #GimpDisplayShell
* @x: returns image x coordinate of display upper left corner
* @y: returns image y coordinate of display upper left corner
* @width: returns width of display measured in image coordinates
* @height: returns height of display measured in image coordinates
*
* This function calculates the part of the image, im image coordinates,
* that corresponds to the display viewport.
**/
void
gimp_display_shell_untransform_viewport (GimpDisplayShell *shell,
gint *x,
gint *y,
gint *width,
gint *height)
{
gint x1, y1, x2, y2;
g_return_if_fail (GIMP_IS_DISPLAY_SHELL (shell));
gimp_display_shell_untransform_xy (shell,
0, 0,
&x1, &y1,
FALSE, FALSE);
gimp_display_shell_untransform_xy (shell,
shell->disp_width, shell->disp_height,
&x2, &y2,
FALSE, FALSE);
if (x1 < 0) x1 = 0;
if (y1 < 0) y1 = 0;
if (x2 > shell->display->image->width) x2 = shell->display->image->width;
if (y2 > shell->display->image->height) y2 = shell->display->image->height;
if (x) *x = x1;
if (y) *y = y1;
if (width) *width = x2 - x1;
if (height) *height = y2 - y1;
}
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