app/magnify.c

   1 /* Dia -- an diagram creation/manipulation program
   2  * Copyright (C) 1998 Alexander Larsson
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18 #include <config.h>
  19 #include <stdlib.h>
  20 #include <math.h>
  21
  22 #include "magnify.h"
  23 #include "cursor.h"
  24
  25 static void
  26 magnify_button_press(MagnifyTool *tool, GdkEventButton *event,
  27                      DDisplay *ddisp)
  28 {
  29   tool->x = tool->oldx = event->x;
  30   tool->y = tool->oldy = event->y;
  31   tool->box_active = TRUE;
  32   tool->moved = FALSE;
  33   gdk_pointer_grab (ddisp->canvas->window, FALSE,
  34                     GDK_POINTER_MOTION_HINT_MASK | GDK_BUTTON1_MOTION_MASK | GDK_BUTTON_RELEASE_MASK,
  35                     NULL, NULL, event->time);
  36 }
  37
  38 static void
  39 magnify_button_release(MagnifyTool *tool, GdkEventButton *event,
  40                        DDisplay *ddisp)
  41 {
  42   Rectangle *visible;
  43   Point p1, p2, tl;
  44   real diff;
  45   int idiff;
  46   real factor;
  47
  48   tool->box_active = FALSE;
  49
  50   visible = &ddisp->visible;
  51
  52   ddisplay_untransform_coords(ddisp, tool->x, tool->y, &p1.x, &p1.y);
  53   ddisplay_untransform_coords(ddisp, event->x, event->y, &p2.x, &p2.y);
  54
  55   tl.x = MIN(p1.x, p2.x);
  56   tl.y = MIN(p1.y, p2.y);
  57
  58   diff = MAX(fabs(p2.x - p1.x), fabs(p2.y - p1.y));
  59   idiff = MAX(abs(tool->x - event->x), abs(tool->y - event->y));
  60
  61   if (tool->moved) {
  62     if (idiff <= 4) {
  63       ddisplay_add_update_all(ddisp);
  64       ddisplay_flush(ddisp);
  65     } else if (!(event->state & GDK_CONTROL_MASK)) {
  66       factor = (visible->right - visible->left) / diff;
  67       tl.x += (visible->right - visible->left)/(2.0*factor);
  68       tl.y += (visible->bottom - visible->top)/(2.0*factor);
  69       ddisplay_zoom(ddisp, &tl, factor);
  70     } else {
  71       factor = diff / (visible->right - visible->left);
  72       tl.x = tl.x * factor + tl.x;
  73       tl.y = tl.y * factor + tl.y;
  74       ddisplay_zoom(ddisp, &tl, factor);
  75     }
  76   } else {
  77     if (event->state & GDK_SHIFT_MASK)
  78       ddisplay_zoom(ddisp, &tl, 0.5);
  79     else
  80       ddisplay_zoom(ddisp, &tl, 2.0);
  81   }
  82
  83   gdk_pointer_ungrab (event->time);
  84 }
  85
  86 typedef struct intPoint { int x,y; } intPoint;
  87
  88 static void
  89 magnify_motion(MagnifyTool *tool, GdkEventMotion *event,
  90                DDisplay *ddisp)
  91 {
  92   intPoint tl, br;
  93
  94   if (tool->box_active) {
  95     tool->moved = TRUE;
  96
  97     if (tool->gc == NULL) {
  98       tool->gc = gdk_gc_new(ddisp->canvas->window);
  99       gdk_gc_set_line_attributes(tool->gc, 1, GDK_LINE_ON_OFF_DASH,
 100                                  GDK_CAP_BUTT, GDK_JOIN_MITER);
 101       gdk_gc_set_foreground(tool->gc, &color_gdk_white);
 102       gdk_gc_set_function(tool->gc, GDK_XOR);
 103     }
 104
 105     tl.x = MIN(tool->x, tool->oldx); tl.y = MIN(tool->y, tool->oldy);
 106     br.x = MAX(tool->x, tool->oldx); br.y = MAX(tool->y, tool->oldy);
 107
 108     gdk_draw_rectangle (ddisp->canvas->window,
 109                         tool->gc, FALSE, tl.x, tl.y, br.x - tl.x, br.y - tl.y);
 110
 111     tl.x = MIN(tool->x, event->x); tl.y = MIN(tool->y, event->y);
 112     br.x = MAX(tool->x, event->x); br.y = MAX(tool->y, event->y);
 113
 114     gdk_draw_rectangle (ddisp->canvas->window,
 115                         tool->gc, FALSE, tl.x, tl.y, br.x - tl.x, br.y - tl.y);
 116
 117     tool->oldx = event->x;
 118     tool->oldy = event->y;
 119   }
 120 }
 121
 122 void
 123 set_zoom_out(Tool *tool)
 124 {
 125   ((MagnifyTool *)tool)->zoom_out = TRUE;
 126   ddisplay_set_all_cursor(get_cursor(CURSOR_ZOOM_OUT));
 127 }
 128
 129 void
 130 set_zoom_in(Tool *tool)
 131 {
 132   ((MagnifyTool *)tool)->zoom_out = FALSE;
 133   ddisplay_set_all_cursor(get_cursor(CURSOR_ZOOM_IN));
 134 }
 135
 136 Tool *
 137 create_magnify_tool(void)
 138 {
 139   MagnifyTool *tool;
 140
 141   tool = g_new0(MagnifyTool, 1);
 142   tool->tool.type = MAGNIFY_TOOL;
 143   tool->tool.button_press_func = (ButtonPressFunc) &magnify_button_press;
 144   tool->tool.button_release_func = (ButtonPressFunc) &magnify_button_release;
 145   tool->tool.motion_func = (MotionFunc) &magnify_motion;
 146   tool->tool.double_click_func = NULL;
 147
 148   tool->gc = NULL;
 149   tool->box_active = FALSE;
 150   tool->zoom_out = FALSE;
 151
 152   ddisplay_set_all_cursor(get_cursor(CURSOR_ZOOM_IN));
 153
 154   return (Tool *) tool;
 155 }
 156
 157 void
 158 free_magnify_tool(Tool *tool)
 159 {
 160   g_free(tool);
 161   ddisplay_set_all_cursor(default_cursor);
 162 }