880 lines
20 KiB
C
880 lines
20 KiB
C
/* PIKA - Photo and Image Kooker Application
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* a rebranding of The GNU Image Manipulation Program (created with heckimp)
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* A derived work which may be trivial. However, any changes may be (C)2023 by Aldercone Studio
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*
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* Original copyright, applying to most contents (license remains unchanged):
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* Copyright (C) 1995-1999 Spencer Kimball and Peter Mattis
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*
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* pikaink-blob.c: routines for manipulating scan converted convex polygons.
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* Copyright 1998-1999, Owen Taylor <otaylor@gtk.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include <glib-object.h>
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#include "libpikamath/pikamath.h"
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#include "paint-types.h"
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#include "pikaink-blob.h"
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typedef enum
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{
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EDGE_NONE = 0,
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EDGE_LEFT = 1 << 0,
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EDGE_RIGHT = 1 << 1
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} EdgeType;
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/* local function prototypes */
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static PikaBlob * pika_blob_new (gint y,
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gint height);
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static void pika_blob_fill (PikaBlob *b,
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EdgeType *present);
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static void pika_blob_make_convex (PikaBlob *b,
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EdgeType *present);
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#if 0
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static void pika_blob_line_add_pixel (PikaBlob *b,
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gint x,
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gint y);
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static void pika_blob_line (PikaBlob *b,
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gint x0,
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gint y0,
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gint x1,
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gint y1);
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#endif
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/* public functions */
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/* Return blob for the given (convex) polygon
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*/
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PikaBlob *
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pika_blob_polygon (PikaBlobPoint *points,
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gint n_points)
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{
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PikaBlob *result;
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EdgeType *present;
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gint i;
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gint im1;
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gint ip1;
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gint ymin, ymax;
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ymax = points[0].y;
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ymin = points[0].y;
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for (i = 1; i < n_points; i++)
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{
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if (points[i].y > ymax)
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ymax = points[i].y;
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if (points[i].y < ymin)
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ymin = points[i].y;
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}
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result = pika_blob_new (ymin, ymax - ymin + 1);
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present = g_new0 (EdgeType, result->height);
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im1 = n_points - 1;
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i = 0;
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ip1 = 1;
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for (; i < n_points ; i++)
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{
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gint sides = 0;
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gint j = points[i].y - ymin;
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if (points[i].y < points[im1].y)
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sides |= EDGE_RIGHT;
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else if (points[i].y > points[im1].y)
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sides |= EDGE_LEFT;
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if (points[ip1].y < points[i].y)
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sides |= EDGE_RIGHT;
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else if (points[ip1].y > points[i].y)
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sides |= EDGE_LEFT;
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if (sides & EDGE_RIGHT)
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{
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if (present[j] & EDGE_RIGHT)
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{
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result->data[j].right = MAX (result->data[j].right, points[i].x);
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}
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else
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{
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present[j] |= EDGE_RIGHT;
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result->data[j].right = points[i].x;
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}
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}
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if (sides & EDGE_LEFT)
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{
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if (present[j] & EDGE_LEFT)
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{
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result->data[j].left = MIN (result->data[j].left, points[i].x);
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}
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else
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{
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present[j] |= EDGE_LEFT;
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result->data[j].left = points[i].x;
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}
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}
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im1 = i;
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ip1++;
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if (ip1 == n_points)
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ip1 = 0;
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}
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pika_blob_fill (result, present);
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g_free (present);
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return result;
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}
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/* Scan convert a square specified by _offsets_ of major and minor
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* axes, and by center into a blob
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*/
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PikaBlob *
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pika_blob_square (gdouble xc,
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gdouble yc,
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gdouble xp,
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gdouble yp,
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gdouble xq,
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gdouble yq)
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{
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PikaBlobPoint points[4];
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/* Make sure we order points ccw */
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if (xp * yq - xq * yp < 0)
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{
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xq = -xq;
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yq = -yq;
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}
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points[0].x = xc + xp + xq;
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points[0].y = yc + yp + yq;
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points[1].x = xc + xp - xq;
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points[1].y = yc + yp - yq;
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points[2].x = xc - xp - xq;
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points[2].y = yc - yp - yq;
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points[3].x = xc - xp + xq;
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points[3].y = yc - yp + yq;
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return pika_blob_polygon (points, 4);
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}
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/* Scan convert a diamond specified by _offsets_ of major and minor
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* axes, and by center into a blob
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*/
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PikaBlob *
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pika_blob_diamond (gdouble xc,
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gdouble yc,
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gdouble xp,
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gdouble yp,
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gdouble xq,
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gdouble yq)
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{
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PikaBlobPoint points[4];
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/* Make sure we order points ccw */
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if (xp * yq - xq * yp < 0)
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{
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xq = -xq;
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yq = -yq;
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}
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points[0].x = xc + xp;
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points[0].y = yc + yp;
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points[1].x = xc - xq;
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points[1].y = yc - yq;
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points[2].x = xc - xp;
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points[2].y = yc - yp;
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points[3].x = xc + xq;
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points[3].y = yc + yq;
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return pika_blob_polygon (points, 4);
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}
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#define TABLE_SIZE 256
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#define ELLIPSE_SHIFT 2
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#define TABLE_SHIFT 12
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#define TOTAL_SHIFT (ELLIPSE_SHIFT + TABLE_SHIFT)
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/*
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* The choose of this values limits the maximal image_size to
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* 16384 x 16384 pixels. The values will overflow as soon as
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* x or y > INT_MAX / (1 << (ELLIPSE_SHIFT + TABLE_SHIFT)) / SUBSAMPLE
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*
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* Alternatively the code could be change the code as follows:
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*
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* xc_base = floor (xc)
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* xc_shift = 0.5 + (xc - xc_base) * (1 << TOTAL_SHIFT);
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*
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* gint x = xc_base + (xc_shift + c * xp_shift + s * xq_shift +
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* (1 << (TOTAL_SHIFT - 1))) >> TOTAL_SHIFT;
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*
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* which would change the limit from the image to the ellipse size
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*
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* Update: this change was done, and now there apparently is a limit
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* on the ellipse size. I'm too lazy to fully understand what's going
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* on here and simply leave this comment here for
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* documentation. --Mitch
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*/
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static gboolean trig_initialized = FALSE;
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static gint trig_table[TABLE_SIZE];
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/* Scan convert an ellipse specified by _offsets_ of major and
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* minor axes, and by center into a blob
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*/
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PikaBlob *
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pika_blob_ellipse (gdouble xc,
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gdouble yc,
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gdouble xp,
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gdouble yp,
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gdouble xq,
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gdouble yq)
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{
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PikaBlob *result;
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EdgeType *present;
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gint i;
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gdouble r1, r2;
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gint maxy, miny;
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gint step;
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gdouble max_radius;
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gint xc_shift, yc_shift;
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gint xp_shift, yp_shift;
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gint xq_shift, yq_shift;
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gint xc_base, yc_base;
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if (! trig_initialized)
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{
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trig_initialized = TRUE;
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for (i = 0; i < 256; i++)
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trig_table[i] = 0.5 + sin (i * (G_PI / 128.0)) * (1 << TABLE_SHIFT);
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}
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/* Make sure we traverse ellipse in ccw direction */
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if (xp * yq - xq * yp < 0)
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{
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xq = -xq;
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yq = -yq;
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}
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/* Compute bounds as if we were drawing a rectangle */
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maxy = ceil (yc + fabs (yp) + fabs (yq));
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miny = floor (yc - fabs (yp) - fabs (yq));
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result = pika_blob_new (miny, maxy - miny + 1);
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present = g_new0 (EdgeType, result->height);
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xc_base = floor (xc);
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yc_base = floor (yc);
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/* Figure out a step that will draw most of the points */
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r1 = sqrt (xp * xp + yp * yp);
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r2 = sqrt (xq * xq + yq * yq);
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max_radius = MAX (r1, r2);
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step = TABLE_SIZE;
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while (step > 1 && (TABLE_SIZE / step < 4 * max_radius))
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step >>= 1;
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/* Fill in the edge points */
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xc_shift = 0.5 + (xc - xc_base) * (1 << TOTAL_SHIFT);
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yc_shift = 0.5 + (yc - yc_base) * (1 << TOTAL_SHIFT);
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xp_shift = 0.5 + xp * (1 << ELLIPSE_SHIFT);
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yp_shift = 0.5 + yp * (1 << ELLIPSE_SHIFT);
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xq_shift = 0.5 + xq * (1 << ELLIPSE_SHIFT);
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yq_shift = 0.5 + yq * (1 << ELLIPSE_SHIFT);
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for (i = 0 ; i < TABLE_SIZE ; i += step)
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{
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gint s = trig_table[i];
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gint c = trig_table[(TABLE_SIZE + TABLE_SIZE / 4 - i) % TABLE_SIZE];
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gint x = ((xc_shift + c * xp_shift + s * xq_shift +
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(1 << (TOTAL_SHIFT - 1))) >> TOTAL_SHIFT) + xc_base;
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gint y = (((yc_shift + c * yp_shift + s * yq_shift +
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(1 << (TOTAL_SHIFT - 1))) >> TOTAL_SHIFT)) + yc_base
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- result->y;
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gint dydi = c * yq_shift - s * yp_shift;
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if (dydi <= 0) /* left edge */
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{
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if (present[y] & EDGE_LEFT)
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{
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result->data[y].left = MIN (result->data[y].left, x);
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}
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else
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{
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present[y] |= EDGE_LEFT;
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result->data[y].left = x;
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}
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}
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if (dydi >= 0) /* right edge */
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{
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if (present[y] & EDGE_RIGHT)
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{
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result->data[y].right = MAX (result->data[y].right, x);
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}
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else
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{
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present[y] |= EDGE_RIGHT;
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result->data[y].right = x;
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}
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}
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}
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/* Now fill in missing points */
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pika_blob_fill (result, present);
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g_free (present);
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return result;
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}
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void
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pika_blob_bounds (PikaBlob *b,
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gint *x,
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gint *y,
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gint *width,
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gint *height)
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{
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gint i;
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gint x0, x1, y0, y1;
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i = 0;
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while (i < b->height && b->data[i].left > b->data[i].right)
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i++;
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if (i < b->height)
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{
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y0 = b->y + i;
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x0 = b->data[i].left;
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x1 = b->data[i].right + 1;
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while (i < b->height && b->data[i].left <= b->data[i].right)
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{
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x0 = MIN (b->data[i].left, x0);
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x1 = MAX (b->data[i].right + 1, x1);
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i++;
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}
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y1 = b->y + i;
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}
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else
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{
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x0 = y0 = 0;
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x1 = y1 = 0;
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}
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*x = x0;
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*y = y0;
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*width = x1 - x0;
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*height = y1 - y0;
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}
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PikaBlob *
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pika_blob_convex_union (PikaBlob *b1,
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PikaBlob *b2)
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{
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PikaBlob *result;
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gint y;
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gint i, j;
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EdgeType *present;
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/* Create the storage for the result */
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y = MIN (b1->y, b2->y);
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result = pika_blob_new (y, MAX (b1->y + b1->height, b2->y + b2->height)-y);
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if (result->height == 0)
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return result;
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present = g_new0 (EdgeType, result->height);
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/* Initialize spans from original objects */
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for (i = 0, j = b1->y-y; i < b1->height; i++, j++)
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{
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if (b1->data[i].right >= b1->data[i].left)
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{
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present[j] = EDGE_LEFT | EDGE_RIGHT;
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result->data[j].left = b1->data[i].left;
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result->data[j].right = b1->data[i].right;
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}
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}
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for (i = 0, j = b2->y - y; i < b2->height; i++, j++)
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{
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if (b2->data[i].right >= b2->data[i].left)
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{
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if (present[j])
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{
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if (result->data[j].left > b2->data[i].left)
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result->data[j].left = b2->data[i].left;
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if (result->data[j].right < b2->data[i].right)
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result->data[j].right = b2->data[i].right;
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}
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else
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{
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present[j] = EDGE_LEFT | EDGE_RIGHT;
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result->data[j].left = b2->data[i].left;
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result->data[j].right = b2->data[i].right;
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}
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}
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}
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pika_blob_make_convex (result, present);
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g_free (present);
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return result;
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}
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PikaBlob *
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pika_blob_duplicate (PikaBlob *b)
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{
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g_return_val_if_fail (b != NULL, NULL);
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return g_memdup2 (b, sizeof (PikaBlob) + sizeof (PikaBlobSpan) * (b->height - 1));
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}
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#if 0
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void
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pika_blob_dump (PikaBlob *b)
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{
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gint i,j;
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for (i = 0; i < b->height; i++)
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{
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for (j = 0; j < b->data[i].left; j++)
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putchar (' ');
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for (j = b->data[i].left; j <= b->data[i].right; j++)
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putchar ('*');
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putchar ('\n');
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}
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}
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#endif
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/* private functions */
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static PikaBlob *
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pika_blob_new (gint y,
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gint height)
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{
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PikaBlob *result;
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result = g_malloc (sizeof (PikaBlob) + sizeof (PikaBlobSpan) * (height - 1));
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result->y = y;
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result->height = height;
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return result;
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}
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static void
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pika_blob_fill (PikaBlob *b,
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EdgeType *present)
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{
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gint start;
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gint x1, x2, i1, i2;
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gint i;
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/* Mark empty lines at top and bottom as unused */
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start = 0;
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while (! present[start])
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{
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b->data[start].left = 0;
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b->data[start].right = -1;
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start++;
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}
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if (present[start] != (EDGE_RIGHT | EDGE_LEFT))
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{
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if (present[start] == EDGE_RIGHT)
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b->data[start].left = b->data[start].right;
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else
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b->data[start].right = b->data[start].left;
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present[start] = EDGE_RIGHT | EDGE_LEFT;
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}
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for (i = b->height - 1; ! present[i]; i--)
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{
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b->data[i].left = 0;
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b->data[i].right = -1;
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}
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if (present[i] != (EDGE_RIGHT | EDGE_LEFT))
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{
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if (present[i] == EDGE_RIGHT)
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b->data[i].left = b->data[i].right;
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else
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b->data[i].right = b->data[i].left;
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present[i] = EDGE_RIGHT | EDGE_LEFT;
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}
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/* Restore missing edges */
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/* We fill only interior regions of convex hull, as if we were
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* filling polygons. But since we draw ellipses with nearest points,
|
|
* not interior points, maybe it would look better if we did the
|
|
* same here. Probably not a big deal either way after anti-aliasing
|
|
*/
|
|
|
|
/* left edge */
|
|
for (i1 = start; i1 < b->height - 2; i1++)
|
|
{
|
|
/* Find empty gaps */
|
|
if (! (present[i1 + 1] & EDGE_LEFT))
|
|
{
|
|
gint increment; /* fractional part */
|
|
gint denom; /* denominator of fraction */
|
|
gint step; /* integral step */
|
|
gint frac; /* fractional step */
|
|
gint reverse;
|
|
|
|
/* find bottom of gap */
|
|
i2 = i1 + 2;
|
|
while (i2 < b->height && ! (present[i2] & EDGE_LEFT))
|
|
i2++;
|
|
|
|
if (i2 < b->height)
|
|
{
|
|
denom = i2 - i1;
|
|
x1 = b->data[i1].left;
|
|
x2 = b->data[i2].left;
|
|
step = (x2 - x1) / denom;
|
|
frac = x2 - x1 - step * denom;
|
|
if (frac < 0)
|
|
{
|
|
frac = -frac;
|
|
reverse = 1;
|
|
}
|
|
else
|
|
reverse = 0;
|
|
|
|
increment = 0;
|
|
for (i = i1 + 1; i < i2; i++)
|
|
{
|
|
x1 += step;
|
|
increment += frac;
|
|
if (increment >= denom)
|
|
{
|
|
increment -= denom;
|
|
x1 += reverse ? -1 : 1;
|
|
}
|
|
if (increment == 0 || reverse)
|
|
b->data[i].left = x1;
|
|
else
|
|
b->data[i].left = x1 + 1;
|
|
}
|
|
}
|
|
|
|
i1 = i2 - 1; /* advance to next possibility */
|
|
}
|
|
}
|
|
|
|
/* right edge */
|
|
for (i1 = start; i1 < b->height - 2; i1++)
|
|
{
|
|
/* Find empty gaps */
|
|
if (! (present[i1 + 1] & EDGE_RIGHT))
|
|
{
|
|
gint increment; /* fractional part */
|
|
gint denom; /* denominator of fraction */
|
|
gint step; /* integral step */
|
|
gint frac; /* fractional step */
|
|
gint reverse;
|
|
|
|
/* find bottom of gap */
|
|
i2 = i1 + 2;
|
|
while (i2 < b->height && ! (present[i2] & EDGE_RIGHT))
|
|
i2++;
|
|
|
|
if (i2 < b->height)
|
|
{
|
|
denom = i2 - i1;
|
|
x1 = b->data[i1].right;
|
|
x2 = b->data[i2].right;
|
|
step = (x2 - x1) / denom;
|
|
frac = x2 - x1 - step * denom;
|
|
if (frac < 0)
|
|
{
|
|
frac = -frac;
|
|
reverse = 1;
|
|
}
|
|
else
|
|
reverse = 0;
|
|
|
|
increment = 0;
|
|
for (i = i1 + 1; i<i2; i++)
|
|
{
|
|
x1 += step;
|
|
increment += frac;
|
|
if (increment >= denom)
|
|
{
|
|
increment -= denom;
|
|
x1 += reverse ? -1 : 1;
|
|
}
|
|
if (reverse && increment != 0)
|
|
b->data[i].right = x1 - 1;
|
|
else
|
|
b->data[i].right = x1;
|
|
}
|
|
}
|
|
|
|
i1 = i2 - 1; /* advance to next possibility */
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
static void
|
|
pika_blob_make_convex (PikaBlob *b,
|
|
EdgeType *present)
|
|
{
|
|
gint x1, x2, y1, y2, i1, i2;
|
|
gint i;
|
|
gint start;
|
|
|
|
/* Walk through edges, deleting points that aren't on convex hull */
|
|
|
|
start = 0;
|
|
while (! present[start])
|
|
start++;
|
|
|
|
/* left edge */
|
|
|
|
i1 = start - 1;
|
|
i2 = start;
|
|
x1 = b->data[start].left - b->data[start].right;
|
|
y1 = 0;
|
|
|
|
for (i = start + 1; i < b->height; i++)
|
|
{
|
|
if (! (present[i] & EDGE_LEFT))
|
|
continue;
|
|
|
|
x2 = b->data[i].left - b->data[i2].left;
|
|
y2 = i - i2;
|
|
|
|
while (x2 * y1 - x1 * y2 < 0) /* clockwise rotation */
|
|
{
|
|
present[i2] &= ~EDGE_LEFT;
|
|
i2 = i1;
|
|
while ((--i1) >= start && (! (present[i1] & EDGE_LEFT)));
|
|
|
|
if (i1 < start)
|
|
{
|
|
x1 = b->data[start].left - b->data[start].right;
|
|
y1 = 0;
|
|
}
|
|
else
|
|
{
|
|
x1 = b->data[i2].left - b->data[i1].left;
|
|
y1 = i2 - i1;
|
|
}
|
|
x2 = b->data[i].left - b->data[i2].left;
|
|
y2 = i - i2;
|
|
}
|
|
|
|
x1 = x2;
|
|
y1 = y2;
|
|
i1 = i2;
|
|
i2 = i;
|
|
}
|
|
|
|
/* Right edge */
|
|
|
|
i1 = start -1;
|
|
i2 = start;
|
|
x1 = b->data[start].right - b->data[start].left;
|
|
y1 = 0;
|
|
|
|
for (i = start + 1; i < b->height; i++)
|
|
{
|
|
if (! (present[i] & EDGE_RIGHT))
|
|
continue;
|
|
|
|
x2 = b->data[i].right - b->data[i2].right;
|
|
y2 = i - i2;
|
|
|
|
while (x2 * y1 - x1 * y2 > 0) /* counter-clockwise rotation */
|
|
{
|
|
present[i2] &= ~EDGE_RIGHT;
|
|
i2 = i1;
|
|
while ((--i1) >= start && (! (present[i1] & EDGE_RIGHT)));
|
|
|
|
if (i1 < start)
|
|
{
|
|
x1 = b->data[start].right - b->data[start].left;
|
|
y1 = 0;
|
|
}
|
|
else
|
|
{
|
|
x1 = b->data[i2].right - b->data[i1].right;
|
|
y1 = i2 - i1;
|
|
}
|
|
|
|
x2 = b->data[i].right - b->data[i2].right;
|
|
y2 = i - i2;
|
|
}
|
|
|
|
x1 = x2;
|
|
y1 = y2;
|
|
i1 = i2;
|
|
i2 = i;
|
|
}
|
|
|
|
pika_blob_fill (b, present);
|
|
}
|
|
|
|
|
|
#if 0
|
|
|
|
static void
|
|
pika_blob_line_add_pixel (PikaBlob *b,
|
|
gint x,
|
|
gint y)
|
|
{
|
|
if (b->data[y - b->y].left > b->data[y - b->y].right)
|
|
{
|
|
b->data[y - b->y].left = b->data[y - b->y].right = x;
|
|
}
|
|
else
|
|
{
|
|
b->data[y - b->y].left = MIN (b->data[y - b->y].left, x);
|
|
b->data[y - b->y].right = MAX (b->data[y - b->y].right, x);
|
|
}
|
|
}
|
|
|
|
static void
|
|
pika_blob_line (PikaBlob *b,
|
|
gint x0,
|
|
gint y0,
|
|
gint x1,
|
|
gint y1)
|
|
{
|
|
gint dx, dy, d;
|
|
gint incrE, incrNE;
|
|
gint x, y;
|
|
|
|
gint xstep = 1;
|
|
gint ystep = 1;
|
|
|
|
dx = x1 - x0;
|
|
dy = y1 - y0;
|
|
|
|
if (dx < 0)
|
|
{
|
|
dx = -dx;
|
|
xstep = -1;
|
|
}
|
|
|
|
if (dy < 0)
|
|
{
|
|
dy = -dy;
|
|
ystep = -1;
|
|
}
|
|
|
|
/* for (y = y0; y != y1 + ystep ; y += ystep)
|
|
{
|
|
b->data[y-b->y].left = 0;
|
|
b->data[y-b->y].right = -1;
|
|
}*/
|
|
|
|
x = x0;
|
|
y = y0;
|
|
|
|
if (dy < dx)
|
|
{
|
|
d = 2 * dy - dx; /* initial value of d */
|
|
incrE = 2 * dy; /* increment used for move to E */
|
|
incrNE = 2 * (dy - dx); /* increment used for move to NE */
|
|
|
|
pika_blob_line_add_pixel (b, x, y);
|
|
|
|
while (x != x1)
|
|
{
|
|
if (d <= 0)
|
|
{
|
|
d += incrE;
|
|
x += xstep;
|
|
}
|
|
else
|
|
{
|
|
d += incrNE;
|
|
x += xstep;
|
|
y += ystep;
|
|
}
|
|
|
|
pika_blob_line_add_pixel (b, x, y);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
d = 2 * dx - dy; /* initial value of d */
|
|
incrE = 2 * dx; /* increment used for move to E */
|
|
incrNE = 2 * (dx - dy); /* increment used for move to NE */
|
|
|
|
pika_blob_line_add_pixel (b, x, y);
|
|
|
|
while (y != y1)
|
|
{
|
|
if (d <= 0)
|
|
{
|
|
d += incrE;
|
|
y += ystep;
|
|
}
|
|
else
|
|
{
|
|
d += incrNE;
|
|
x += xstep;
|
|
y += ystep;
|
|
}
|
|
|
|
pika_blob_line_add_pixel (b, x, y);
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif
|
