/* * Copyright (C) 1995 Spencer Kimball and Peter Mattis * * This is a plug-in for the GIMP. * * Generates images containing vector type drawings. * * Copyright (C) 1997 Andy Thomas alt@picnic.demon.co.uk * * 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 #include #include #include #include #include "gfig.h" #include "gfig-grid.h" #include "libgimp/stdplugins-intl.h" /* For the isometric grid */ #define SQRT3 1.73205080756887729353 /* Square root of 3 */ #define SIN_1o6PI_RAD 0.5 /* Sine 1/6 Pi Radians */ #define COS_1o6PI_RAD SQRT3 / 2 /* Cosine 1/6 Pi Radians */ #define TAN_1o6PI_RAD 1 / SQRT3 /* Tangent 1/6 Pi Radians == SIN / COS */ #define RECIP_TAN_1o6PI_RAD SQRT3 /* Reciprocal of Tangent 1/6 Pi Radians */ static GdkGC *grid_hightlight_drawgc; gint grid_gc_type = GTK_STATE_NORMAL; static void draw_grid_polar (GdkGC *drawgc); static void draw_grid_sq (GdkGC *drawgc); static void draw_grid_iso (GdkGC *drawgc); static GdkGC *gfig_get_grid_gc (GtkWidget *widget, gint gctype); static gint get_num_radials (void); /* find_grid_pos - Given an x, y point return the grid position of it */ /* return the new position in the passed point */ void gfig_grid_colours (GtkWidget *widget) { GdkColormap *colormap; GdkGCValues values; GdkColor col1; GdkColor col2; guchar stipple[8] = { 0xAA, /* ####---- */ 0x55, /* ###----# */ 0xAA, /* ##----## */ 0x55, /* #----### */ 0xAA, /* ----#### */ 0x55, /* ---####- */ 0xAA, /* --####-- */ 0x55, /* -####--- */ }; colormap = gdk_screen_get_rgb_colormap (gtk_widget_get_screen (widget)); gdk_color_parse ("gray50", &col1); gdk_colormap_alloc_color (colormap, &col1, FALSE, TRUE); gdk_color_parse ("gray80", &col2); gdk_colormap_alloc_color (colormap, &col2, FALSE, TRUE); values.background.pixel = col1.pixel; values.foreground.pixel = col2.pixel; values.fill = GDK_OPAQUE_STIPPLED; values.stipple = gdk_bitmap_create_from_data (widget->window, (gchar *) stipple, 4, 4); grid_hightlight_drawgc = gdk_gc_new_with_values (widget->window, &values, GDK_GC_FOREGROUND | GDK_GC_BACKGROUND | GDK_GC_FILL | GDK_GC_STIPPLE); } void find_grid_pos (GdkPoint *p, GdkPoint *gp, guint is_butt3) { gint16 x = p->x; gint16 y = p->y; static GdkPoint cons_pnt; static gdouble cons_radius; static gdouble cons_ang; static gboolean cons_center; if (selvals.opts.gridtype == RECT_GRID) { if (p->x % selvals.opts.gridspacing > selvals.opts.gridspacing/2) x += selvals.opts.gridspacing; if (p->y % selvals.opts.gridspacing > selvals.opts.gridspacing/2) y += selvals.opts.gridspacing; gp->x = (x/selvals.opts.gridspacing)*selvals.opts.gridspacing; gp->y = (y/selvals.opts.gridspacing)*selvals.opts.gridspacing; if (is_butt3) { if (abs (gp->x - cons_pnt.x) < abs (gp->y - cons_pnt.y)) gp->x = cons_pnt.x; else gp->y = cons_pnt.y; } else { /* Store the point since might be used later */ cons_pnt = *gp; /* Structure copy */ } } else if (selvals.opts.gridtype == POLAR_GRID) { gdouble ang_grid; gdouble ang_radius; gdouble real_radius; gdouble real_angle; gdouble rounded_angle; gint rounded_radius; gint16 shift_x = x - preview_width/2; gint16 shift_y = -y + preview_height/2; real_radius = ang_radius = sqrt ((shift_y*shift_y) + (shift_x*shift_x)); /* round radius */ rounded_radius = (gint)(RINT (ang_radius/selvals.opts.gridspacing))*selvals.opts.gridspacing; if (rounded_radius <= 0 || real_radius <=0) { /* DEAD CENTER */ gp->x = preview_width/2; gp->y = preview_height/2; if (!is_butt3) cons_center = TRUE; #ifdef DEBUG printf ("Dead center\n"); #endif /* DEBUG */ return; } ang_grid = 2*G_PI/get_num_radials (); real_angle = atan2 (shift_y, shift_x); if (real_angle < 0) real_angle += 2*G_PI; rounded_angle = (RINT ((real_angle/ang_grid)))*ang_grid; #ifdef DEBUG printf ("real_ang = %f ang_gid = %f rounded_angle = %f rounded radius = %d\n", real_angle, ang_grid, rounded_angle, rounded_radius); printf ("preview_width = %d preview_height = %d\n", preview_width, preview_height); #endif /* DEBUG */ gp->x = (gint)RINT ((rounded_radius*cos (rounded_angle))) + preview_width/2; gp->y = -(gint)RINT ((rounded_radius*sin (rounded_angle))) + preview_height/2; if (is_butt3) { if (!cons_center) { if (fabs (rounded_angle - cons_ang) > ang_grid/2) { gp->x = (gint)RINT ((cons_radius*cos (rounded_angle))) + preview_width/2; gp->y = -(gint)RINT ((cons_radius*sin (rounded_angle))) + preview_height/2; } else { gp->x = (gint)RINT ((rounded_radius*cos (cons_ang))) + preview_width/2; gp->y = -(gint)RINT ((rounded_radius*sin (cons_ang))) + preview_height/2; } } } else { cons_radius = rounded_radius; cons_ang = rounded_angle; cons_center = FALSE; } } else if (selvals.opts.gridtype == ISO_GRID) { /* * This really needs a picture to show the math... * * Consider an isometric grid with one of the sets of lines parallel to the * y axis (vertical alignment). Further define that the origin of a Cartesian * grid is at a isometric vertex. For simplicity consider the first quadrant only. * * - Let one line segment between vertices be r * - Define the value of r as the grid spacing * - Assign an integer n identifier to each vertical grid line along the x axis. * with n=0 being the y axis. n can be any integer * - Let m to be any integer * - Let h be the spacing between vertical grid lines measured along the x axis. * It follows from the isometric grid that h has a value of r * COS(1/6 Pi Rad) * * Consider a Vertex V at the Cartesian location [Xv, Yv] * * It follows that vertices belong to the set... * V[Xv, Yv] = [ [ n * h ] , * [ m * r + ( 0.5 * r (n % 2) ) ] ] * for all integers n and m * * Who cares? Me. It's useful in solving this problem: * Consider an arbitrary point P[Xp,Yp], find the closest vertex in the set V. * * Restated this problem is "find values for m and n that are drive V closest to P" * * A Solution method (there may be a better one?): * * Step 1) bound n to the two closest values for Xp * n_lo = (int) (Xp / h) * n_hi = n_lo + 1 * * Step 2) Consider the two closes vertices for each n_lo and n_hi. The further of * the vertices in each pair can readily be discarded. * m_lo_n_lo = (int) ( (Yp / r) - 0.5 (n_lo % 2) ) * m_hi_n_lo = m_lo_n_lo + 1 * * m_lo_n_hi = (int) ( (Yp / r) - 0.5 (n_hi % 2) ) * m_hi_n_hi = m_hi_n_hi * * Step 3) compute the distance from P to V1 and V2. Snap to the closer point. */ gint n_lo; gint n_hi; gint m_lo_n_lo; gint m_hi_n_lo; gint m_lo_n_hi; gint m_hi_n_hi; gint m_n_lo; gint m_n_hi; gdouble r; gdouble h; gint x1; gint x2; gint y1; gint y2; r = selvals.opts.gridspacing; h = COS_1o6PI_RAD * r; n_lo = (gint) x / h; n_hi = n_lo + 1; /* evaluate m candidates for n_lo */ m_lo_n_lo = (gint) ( (y / r) - 0.5 * (n_lo % 2) ); m_hi_n_lo = m_lo_n_lo + 1; /* figure out which is the better candidate */ if (abs((m_lo_n_lo * r + (0.5 * r * (n_lo % 2))) - y) < abs((m_hi_n_lo * r + (0.5 * r * (n_lo % 2))) - y)) { m_n_lo = m_lo_n_lo; } else { m_n_lo = m_hi_n_lo; } /* evaluate m candidates for n_hi */ m_lo_n_hi = (gint) ( (y / r) - 0.5 * (n_hi % 2) ); m_hi_n_hi = m_lo_n_hi + 1; /* figure out which is the better candidate */ if (abs((m_lo_n_hi * r + (0.5 * r * (n_hi % 2))) - y) < abs((m_hi_n_hi * r + (0.5 * r * (n_hi % 2))) - y)) { m_n_hi = m_lo_n_hi; } else { m_n_hi = m_hi_n_hi; } /* Now, which is closer to [x,y]? we can use a somewhat abbreviated form of the * distance formula since we only care about relative values. */ x1 = (gint) (n_lo * h); y1 = (gint) (m_n_lo * r + (0.5 * r * (n_lo % 2))); x2 = (gint) (n_hi * h); y2 = (gint) (m_n_hi * r + (0.5 * r * (n_hi % 2))); if (((x - x1) * (x - x1) + (y - y1) * (y - y1)) < ((x - x2) * (x - x2) + (y - y2) * (y - y2))) { gp->x = x1; gp->y = y1; } else { gp->x = x2; gp->y = y2; } } } static void draw_grid_polar (GdkGC *drawgc) { gint step; gint loop; gint radius; gint max_rad; gdouble ang_grid; gdouble ang_loop; gdouble ang_radius; /* Pick center and draw concentric circles */ gint grid_x_center = preview_width/2; gint grid_y_center = preview_height/2; step = selvals.opts.gridspacing; max_rad = sqrt (preview_width * preview_width + preview_height * preview_height) / 2; for (loop = 0; loop < max_rad; loop += step) { radius = loop; gdk_draw_arc (gfig_context->preview->window, drawgc, 0, grid_x_center - radius, grid_y_center - radius, radius*2, radius*2, 0, 360 * 64); } /* Lines */ ang_grid = 2 * G_PI / get_num_radials (); ang_radius = sqrt ((preview_width * preview_width) + (preview_height * preview_height)) / 2; for (loop = 0; loop <= get_num_radials (); loop++) { gint lx, ly; ang_loop = loop * ang_grid; lx = RINT (ang_radius * cos (ang_loop)); ly = RINT (ang_radius * sin (ang_loop)); gdk_draw_line (gfig_context->preview->window, drawgc, lx + (preview_width) / 2, - ly + (preview_height) / 2, (preview_width) / 2, (preview_height) / 2); } } static void draw_grid_sq (GdkGC *drawgc) { gint step; gint loop; /* Draw the horizontal lines */ step = selvals.opts.gridspacing; for (loop = 0 ; loop < preview_height ; loop += step) { gdk_draw_line (gfig_context->preview->window, drawgc, 0, loop, preview_width, loop); } /* Draw the vertical lines */ for (loop = 0 ; loop < preview_width ; loop += step) { gdk_draw_line (gfig_context->preview->window, drawgc, loop, 0, loop, preview_height); } } static void draw_grid_iso (GdkGC *drawgc) { /* vstep is an int since it's defined from grid size */ gint vstep; gdouble loop; gdouble hstep; gdouble diagonal_start; gdouble diagonal_end; gdouble diagonal_width; gdouble diagonal_height; vstep = selvals.opts.gridspacing; hstep = selvals.opts.gridspacing * COS_1o6PI_RAD; /* Draw the vertical lines - These are easy */ for (loop = 0 ; loop < preview_width ; loop += hstep){ gdk_draw_line (gfig_context->preview->window, drawgc, (gint)loop, (gint)0, (gint)loop, (gint)preview_height); } /* draw diag lines at a Theta of +/- 1/6 Pi Rad */ diagonal_start = -(((int)preview_width * TAN_1o6PI_RAD) - (((int)(preview_width * TAN_1o6PI_RAD)) % vstep)); diagonal_end = preview_height + (preview_width * TAN_1o6PI_RAD); diagonal_end -= ((int)diagonal_end) % vstep; diagonal_width = preview_width; diagonal_height = preview_width * TAN_1o6PI_RAD; /* Draw diag lines */ for (loop = diagonal_start ; loop < diagonal_end ; loop += vstep) { gdk_draw_line (gfig_context->preview->window, drawgc, (gint)0, (gint)loop, (gint)diagonal_width, (gint)loop + diagonal_height); gdk_draw_line (gfig_context->preview->window, drawgc, (gint)0, (gint)loop, (gint)diagonal_width, (gint)loop - diagonal_height); } } static GdkGC * gfig_get_grid_gc (GtkWidget *w, gint gctype) { switch (gctype) { case GFIG_BLACK_GC: return (w->style->black_gc); case GFIG_WHITE_GC: return (w->style->white_gc); case GFIG_GREY_GC: return (grid_hightlight_drawgc); case GTK_STATE_NORMAL: return (w->style->bg_gc[GTK_STATE_NORMAL]); case GTK_STATE_ACTIVE: return (w->style->bg_gc[GTK_STATE_ACTIVE]); case GTK_STATE_PRELIGHT: return (w->style->bg_gc[GTK_STATE_PRELIGHT]); case GTK_STATE_SELECTED: return (w->style->bg_gc[GTK_STATE_SELECTED]); case GTK_STATE_INSENSITIVE: return (w->style->bg_gc[GTK_STATE_INSENSITIVE]); default: g_warning ("Unknown type for grid colouring\n"); return (w->style->bg_gc[GTK_STATE_PRELIGHT]); } } void draw_grid (void) { GdkGC *drawgc; /* Get the size of the preview and calc where the lines go */ /* Draw in prelight to start with... */ /* Always start in the upper left corner for rect. */ if ((preview_width < selvals.opts.gridspacing && preview_height < selvals.opts.gridspacing)) { /* Don't draw if they don't fit */ return; } if (selvals.opts.drawgrid) drawgc = gfig_get_grid_gc (gfig_context->preview, grid_gc_type); else return; if (selvals.opts.gridtype == RECT_GRID) draw_grid_sq (drawgc); else if (selvals.opts.gridtype == POLAR_GRID) draw_grid_polar (drawgc); else if (selvals.opts.gridtype == ISO_GRID) draw_grid_iso (drawgc); } static gint get_num_radials (void) { gint gridsp = MAX_GRID + MIN_GRID; /* select number of radials to draw */ /* Either have 16 32 or 48 */ /* correspond to GRID_MAX, midway and GRID_MIN */ return gridsp - selvals.opts.gridspacing; }