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- /* Ripple --- image filter plug-in for The Gimp image manipulation program
- * Copyright (C) 1997 Brian Degenhardt
- *
- * 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.
- *
- * Please direct all comments, questions, bug reports etc to Brian Degenhardt
- * bdegenha@ucsd.edu
- *
- * You can contact the original The Gimp authors at gimp@xcf.berkeley.edu
- */
- #include "config.h"
-
- #include <time.h>
- #include <stdio.h>
- #include <stdlib.h>
-
- #include <gtk/gtk.h>
-
- #include <libgimp/gimp.h>
- #include <libgimp/gimpui.h>
-
- #include "libgimp/stdplugins-intl.h"
-
-
- /* Some useful macros */
- #define SCALE_WIDTH 200
- #define TILE_CACHE_SIZE 16
-
- #define HORIZONTAL 0
- #define VERTICAL 1
-
- #define SMEAR 0
- #define WRAP 1
- #define BLACK 2
-
- #define SAWTOOTH 0
- #define SINE 1
-
- typedef struct
- {
- gint period;
- gint amplitude;
- gint orientation;
- gint edges;
- gint waveform;
- gint antialias;
- gint tile;
- } RippleValues;
-
- typedef struct
- {
- gint run;
- } RippleInterface;
-
-
- /* Declare local functions.
- */
- static void query (void);
- static void run (gchar *name,
- gint nparams,
- GimpParam *param,
- gint *nreturn_vals,
- GimpParam **return_vals);
-
- static void ripple (GimpDrawable *drawable);
-
- static gint ripple_dialog (void);
- static void ripple_ok_callback (GtkWidget *widget,
- gpointer data);
-
- static GimpTile * ripple_pixel (GimpDrawable *drawable,
- GimpTile *tile,
- gint x1,
- gint y1,
- gint x2,
- gint y2,
- gint x,
- gint y,
- gint *row,
- gint *col,
- guchar *pixel);
-
-
- static gdouble displace_amount (gint location);
- static guchar averagetwo (gdouble location,
- guchar *v);
- static guchar averagefour (gdouble location,
- guchar *v);
-
- /***** Local vars *****/
-
- GimpPlugInInfo PLUG_IN_INFO =
- {
- NULL, /* init_proc */
- NULL, /* quit_proc */
- query, /* query_proc */
- run, /* run_proc */
- };
-
- static RippleValues rvals =
- {
- 20, /* period */
- 5, /* amplitude */
- HORIZONTAL, /* orientation */
- WRAP, /* edges */
- SINE, /* waveform */
- TRUE, /* antialias */
- TRUE /* tile */
- };
-
- static RippleInterface rpint =
- {
- FALSE /* run */
- };
-
- /***** Functions *****/
-
- MAIN ()
-
- static void
- query (void)
- {
- static GimpParamDef args[] =
- {
- { GIMP_PDB_INT32, "run_mode", "Interactive, non-interactive" },
- { GIMP_PDB_IMAGE, "image", "Input image (unused)" },
- { GIMP_PDB_DRAWABLE, "drawable", "Input drawable" },
- { GIMP_PDB_INT32, "period", "period; number of pixels for one wave to complete" },
- { GIMP_PDB_INT32, "amplitude", "amplitude; maximum displacement of wave" },
- { GIMP_PDB_INT32, "orientation", "orientation; 0 = Horizontal, 1 = Vertical" },
- { GIMP_PDB_INT32, "edges", "edges; 0 = smear, 1 = wrap, 2 = black" },
- { GIMP_PDB_INT32, "waveform", "0 = sawtooth, 1 = sine wave" },
- { GIMP_PDB_INT32, "antialias", "antialias; True or False" },
- { GIMP_PDB_INT32, "tile", "tile; if this is true, the image will retain it's tilability" }
- };
- static gint nargs = sizeof (args) / sizeof (args[0]);
-
- gimp_install_procedure ("plug_in_ripple",
- "Ripple the contents of the specified drawable",
- "Ripples the pixels of the specified drawable. Each row or column will be displaced a certain number of pixels coinciding with the given wave form",
- "Brian Degenhardt <bdegenha@ucsd.edu>",
- "Brian Degenhardt",
- "1997",
- N_("<Image>/Filters/Distorts/Ripple..."),
- "RGB*, GRAY*",
- GIMP_PLUGIN,
- nargs, 0,
- args, NULL);
- }
-
- static void
- run (gchar *name,
- gint nparams,
- GimpParam *param,
- gint *nreturn_vals,
- GimpParam **return_vals)
- {
- static GimpParam values[1];
- GimpDrawable *drawable;
- GimpRunModeType run_mode;
- GimpPDBStatusType status = GIMP_PDB_SUCCESS;
-
- run_mode = param[0].data.d_int32;
-
- /* Get the specified drawable */
- drawable = gimp_drawable_get (param[2].data.d_drawable);
-
- *nreturn_vals = 1;
- *return_vals = values;
-
- values[0].type = GIMP_PDB_STATUS;
- values[0].data.d_status = status;
-
- switch (run_mode)
- {
- case GIMP_RUN_INTERACTIVE:
- INIT_I18N_UI();
- /* Possibly retrieve data */
- gimp_get_data ("plug_in_ripple", &rvals);
-
- /* First acquire information with a dialog */
- if (! ripple_dialog ())
- return;
- break;
-
- case GIMP_RUN_NONINTERACTIVE:
- INIT_I18N();
- /* Make sure all the arguments are there! */
- if (nparams != 10)
- {
- status = GIMP_PDB_CALLING_ERROR;
- }
- else
- {
- rvals.period = param[3].data.d_int32;
- rvals.amplitude = param[4].data.d_int32;
- rvals.orientation = (param[5].data.d_int32) ? VERTICAL : HORIZONTAL;
- rvals.edges = (param[6].data.d_int32);
- rvals.waveform = param[7].data.d_int32;
- rvals.antialias = (param[8].data.d_int32) ? TRUE : FALSE;
- rvals.tile = (param[9].data.d_int32) ? TRUE : FALSE;
-
- if (rvals.edges < SMEAR || rvals.edges > BLACK)
- status = GIMP_PDB_CALLING_ERROR;
- }
- break;
-
- case GIMP_RUN_WITH_LAST_VALS:
- INIT_I18N();
- /* Possibly retrieve data */
- gimp_get_data ("plug_in_ripple", &rvals);
- break;
-
- default:
- break;
- }
-
- if (status == GIMP_PDB_SUCCESS)
- {
- /* Make sure that the drawable is gray or RGB color */
- if (gimp_drawable_is_rgb (drawable->id) ||
- gimp_drawable_is_gray (drawable->id))
- {
- gimp_progress_init ( _("Rippling..."));
-
- /* set the tile cache size */
- gimp_tile_cache_ntiles (TILE_CACHE_SIZE);
-
- /* run the ripple effect */
- ripple (drawable);
-
- if (run_mode != GIMP_RUN_NONINTERACTIVE)
- gimp_displays_flush ();
-
- /* Store data */
- if (run_mode == GIMP_RUN_INTERACTIVE)
- gimp_set_data ("plug_in_ripple", &rvals, sizeof (RippleValues));
- }
- else
- {
- /* gimp_message ("ripple: cannot operate on indexed color images"); */
- status = GIMP_PDB_EXECUTION_ERROR;
- }
- }
-
- values[0].data.d_status = status;
-
- gimp_drawable_detach (drawable);
- }
-
- static void
- ripple (GimpDrawable *drawable)
- {
- GimpPixelRgn dest_rgn;
- GimpTile * tile = NULL;
- gint row = -1;
- gint col = -1;
- gpointer pr;
-
- gint width, height;
- gint bytes;
- guchar *destline;
- guchar *dest;
- guchar *otherdest;
- guchar pixel[4][4];
- gint x1, y1, x2, y2;
- gint x, y;
- gint progress, max_progress;
- gdouble needx, needy;
-
- guchar values[4];
- guchar val;
-
- gint xi, yi;
-
- gint k;
-
- /* Get selection area */
-
- gimp_drawable_mask_bounds (drawable->id, &x1, &y1, &x2, &y2);
-
- width = drawable->width;
- height = drawable->height;
- bytes = drawable->bpp;
-
- if ( rvals.tile )
- {
- rvals.edges = WRAP;
- rvals.period = (width / (width / rvals.period) *
- (rvals.orientation == HORIZONTAL) +
- height / (height / rvals.period) *
- (rvals.orientation == VERTICAL));
- }
-
- progress = 0;
- max_progress = (x2 - x1) * (y2 - y1);
-
- /* Ripple the image. It's a pretty simple algorithm. If horizontal
- is selected, then every row is displaced a number of pixels that
- follows the pattern of the waveform selected. The effect is
- just reproduced with columns if vertical is selected.
- */
-
- gimp_pixel_rgn_init (&dest_rgn, drawable,
- x1, y1, (x2 - x1), (y2 - y1), TRUE, TRUE);
- for (pr = gimp_pixel_rgns_register (1, &dest_rgn);
- pr != NULL;
- pr = gimp_pixel_rgns_process (pr))
- {
- if (rvals.orientation == VERTICAL)
- {
- destline = dest_rgn.data;
-
- for (x = dest_rgn.x; x < (dest_rgn.x + dest_rgn.w); x++)
- {
- dest = destline;
-
- for (y = dest_rgn.y; y < (dest_rgn.y + dest_rgn.h); y++)
- {
- otherdest = dest;
-
- needy = y + displace_amount(x);
- yi = floor(needy);
-
- /* Tile the image. */
- if (rvals.edges == WRAP)
- {
- needy = fmod(needy + height, height);
- yi = (yi + height) % height;
- }
- /* Smear out the edges of the image by repeating pixels. */
- else if (rvals.edges == SMEAR)
- {
- if (yi < 0)
- yi = 0;
- else if (yi > height - 1)
- yi = height - 1;
- }
-
- if ( rvals.antialias)
- {
- if (yi == height - 1)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *otherdest++ = pixel[0][k];
- }
- else if (needy < 0 && needy > -1)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, 0, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *otherdest++ = pixel[0][k];
- }
-
- else if (yi == height - 2 || yi == 0)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi, &row, &col, pixel[0]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi + 1, &row, &col, pixel[1]);
-
- for (k = 0; k < bytes; k++)
- {
- values[0] = pixel[0][k];
- values[1] = pixel[1][k];
- val = averagetwo(needy, values);
-
- *otherdest++ = val;
- }
- }
- else
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi, &row, &col, pixel[0]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi + 1, &row, &col, pixel[1]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi - 1, &row, &col, pixel[2]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi + 2, &row, &col, pixel[3]);
-
- for (k = 0; k < bytes; k++)
- {
- values[0] = pixel[0][k];
- values[1] = pixel[1][k];
- values[2] = pixel[2][k];
- values[3] = pixel[3][k];
-
- val = averagefour (needy, values);
-
- *otherdest++ = val;
- }
- }
- } /* antialias */
- else
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- x, yi, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *otherdest++ = pixel[0][k];
- }
- dest += dest_rgn.rowstride;
- } /* for */
-
- for (k = 0; k < bytes; k++)
- destline++;
- } /* for */
-
- progress += dest_rgn.w * dest_rgn.h;
- gimp_progress_update ((double) progress / (double) max_progress);
- }
- else /* HORIZONTAL */
- {
- destline = dest_rgn.data;
-
- for (y = dest_rgn.y; y < (dest_rgn.y + dest_rgn.h); y++)
- {
- dest = destline;
-
- for (x = dest_rgn.x; x < (dest_rgn.x + dest_rgn.w); x++)
- {
- needx = x + displace_amount(y);
- xi = floor (needx);
-
- /* Tile the image. */
- if (rvals.edges == WRAP)
- {
- needx = fmod((needx + width), width);
- xi = (xi + width) % width;
- }
- /* Smear out the edges of the image by repeating pixels. */
- else if (rvals.edges == SMEAR)
- {
- if (xi < 0)
- xi = 0;
- else if (xi > width - 1)
- xi = width - 1;
- }
-
- if ( rvals.antialias)
- {
- if (xi == width - 1)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi, y, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *dest++ = pixel[0][k];
- }
- else if (floor(needx) == -1)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- 0, y, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *dest++ = pixel[0][k];
- }
-
- else if (xi == width - 2 || xi == 0)
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi, y, &row, &col, pixel[0]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi + 1, y, &row, &col, pixel[1]);
-
- for (k = 0; k < bytes; k++)
- {
- values[0] = pixel[0][k];
- values[1] = pixel[1][k];
- val = averagetwo (needx, values);
-
- *dest++ = val;
- }
- }
- else
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi, y, &row, &col, pixel[0]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi + 1, y, &row, &col, pixel[1]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi - 1 , y, &row, &col, pixel[2]);
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi + 2, y, &row, &col, pixel[3]);
-
- for (k = 0; k < bytes; k++)
- {
- values[0] = pixel[0][k];
- values[1] = pixel[1][k];
- values[2] = pixel[2][k];
- values[3] = pixel[3][k];
-
- val = averagefour (needx, values);
-
- *dest++ = val;
- }
- }
- } /* antialias */
-
- else
- {
- tile = ripple_pixel (drawable, tile,
- x1, y1, x2, y2,
- xi, y, &row, &col, pixel[0]);
-
- for (k = 0; k < bytes; k++)
- *dest++ = pixel[0][k];
- }
- } /* for */
-
- destline += dest_rgn.rowstride;
- } /* for */
-
- progress += dest_rgn.w * dest_rgn.h;
- gimp_progress_update ((double) progress / (double) max_progress);
- }
- } /* for */
-
- if (tile)
- gimp_tile_unref (tile, FALSE);
-
- /* update the region */
- gimp_drawable_flush (drawable);
- gimp_drawable_merge_shadow (drawable->id, TRUE);
- gimp_drawable_update (drawable->id, x1, y1, (x2 - x1), (y2 - y1));
- } /* ripple */
-
- static gint
- ripple_dialog (void)
- {
- GtkWidget *dlg;
- GtkWidget *toggle;
- GtkWidget *toggle_vbox;
- GtkWidget *main_vbox;
- GtkWidget *frame;
- GtkWidget *table;
- GtkObject *scale_data;
-
- gimp_ui_init ("ripple", TRUE);
-
- dlg = gimp_dialog_new (_("Ripple"), "ripple",
- gimp_standard_help_func, "filters/ripple.html",
- GTK_WIN_POS_MOUSE,
- FALSE, TRUE, FALSE,
-
- _("OK"), ripple_ok_callback,
- NULL, NULL, NULL, TRUE, FALSE,
- _("Cancel"), gtk_widget_destroy,
- NULL, 1, NULL, FALSE, TRUE,
-
- NULL);
-
- gtk_signal_connect (GTK_OBJECT (dlg), "destroy",
- GTK_SIGNAL_FUNC (gtk_main_quit),
- NULL);
-
- /* The main vbox */
- main_vbox = gtk_vbox_new (FALSE, 6);
- gtk_container_set_border_width (GTK_CONTAINER (main_vbox), 6);
- gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dlg)->vbox), main_vbox,
- FALSE, FALSE, 0);
-
- /* The table to hold the four frames of options */
- table = gtk_table_new (2, 2, FALSE);
- gtk_table_set_col_spacings (GTK_TABLE (table), 6);
- gtk_table_set_row_spacings (GTK_TABLE (table), 6);
- gtk_box_pack_start (GTK_BOX (main_vbox), table, FALSE, FALSE, 0);
-
- /* Options section */
- frame = gtk_frame_new ( _("Options"));
- gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_ETCHED_IN);
- gtk_table_attach (GTK_TABLE (table), frame, 0, 1, 0, 1,
- GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 0);
-
- toggle_vbox = gtk_vbox_new (FALSE, 1);
- gtk_container_set_border_width (GTK_CONTAINER (toggle_vbox), 2);
- gtk_container_add (GTK_CONTAINER (frame), toggle_vbox);
-
- toggle = gtk_check_button_new_with_label (_("Antialiasing"));
- gtk_box_pack_start (GTK_BOX (toggle_vbox), toggle, FALSE, FALSE, 0);
- gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
- GTK_SIGNAL_FUNC (gimp_toggle_button_update),
- &rvals.antialias);
- gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), rvals.antialias);
- gtk_widget_show (toggle);
-
- toggle = gtk_check_button_new_with_label ( _("Retain Tilability"));
- gtk_box_pack_start (GTK_BOX (toggle_vbox), toggle, FALSE, FALSE, 0);
- gtk_signal_connect (GTK_OBJECT (toggle), "toggled",
- GTK_SIGNAL_FUNC (gimp_toggle_button_update),
- &rvals.tile);
- gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (toggle), (rvals.tile));
- gtk_widget_show (toggle);
-
- gtk_widget_show (toggle_vbox);
- gtk_widget_show (frame);
-
- /* Orientation toggle box */
- frame =
- gimp_radio_group_new2 (TRUE, _("Orientation"),
- gimp_radio_button_update,
- &rvals.orientation, GINT_TO_POINTER (rvals.orientation),
-
- _("Horizontal"), GINT_TO_POINTER (HORIZONTAL), NULL,
- _("Vertical"), GINT_TO_POINTER (VERTICAL), NULL,
-
- NULL);
- gtk_table_attach (GTK_TABLE (table), frame, 1, 2, 0, 1,
- GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 0);
- gtk_widget_show (frame);
-
- /* Edges toggle box */
- frame = gimp_radio_group_new2 (TRUE, _("Edges"),
- gimp_radio_button_update,
- &rvals.edges, GINT_TO_POINTER (rvals.edges),
-
- _("Wrap"), GINT_TO_POINTER (WRAP), NULL,
- _("Smear"), GINT_TO_POINTER (SMEAR), NULL,
- _("Black"), GINT_TO_POINTER (BLACK), NULL,
-
- NULL);
- gtk_table_attach (GTK_TABLE (table), frame, 0, 1, 1, 2,
- GTK_FILL | GTK_EXPAND, GTK_FILL | GTK_EXPAND, 0, 0);
- gtk_widget_show (frame);
-
- /* Wave toggle box */
- frame = gimp_radio_group_new2 (TRUE, _("Wave Type"),
- gimp_radio_button_update,
- &rvals.waveform, GINT_TO_POINTER (rvals.waveform),
-
- _("Sawtooth"), GINT_TO_POINTER (SAWTOOTH), NULL,
- _("Sine"), GINT_TO_POINTER (SINE), NULL,
-
- NULL);
- gtk_table_attach (GTK_TABLE (table), frame, 1, 2, 1, 2,
- GTK_FILL | GTK_EXPAND, GTK_FILL | GTK_EXPAND, 0, 0);
- gtk_widget_show (frame);
-
- gtk_widget_show (table);
-
- /* Parameter Settings */
- frame = gtk_frame_new ( _("Parameter Settings"));
- gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_ETCHED_IN);
- gtk_box_pack_start (GTK_BOX (main_vbox), frame, FALSE, FALSE, 0);
-
- table = gtk_table_new (2, 3, FALSE);
- gtk_table_set_col_spacings (GTK_TABLE (table), 4);
- gtk_table_set_row_spacings (GTK_TABLE (table), 2);
- gtk_container_set_border_width (GTK_CONTAINER (table), 4);
- gtk_container_add (GTK_CONTAINER (frame), table);
-
- /* Period */
- scale_data = gimp_scale_entry_new (GTK_TABLE (table), 0, 0,
- _("Period:"), SCALE_WIDTH, 0,
- rvals.period, 0, 200, 1, 10, 0,
- TRUE, 0, 0,
- NULL, NULL);
- gtk_signal_connect (GTK_OBJECT (scale_data), "value_changed",
- GTK_SIGNAL_FUNC (gimp_int_adjustment_update),
- &rvals.period);
-
- /* Amplitude */
- scale_data = gimp_scale_entry_new (GTK_TABLE (table), 0, 1,
- _("Amplitude:"), SCALE_WIDTH, 0,
- rvals.amplitude, 0, 200, 1, 10, 0,
- TRUE, 0, 0,
- NULL, NULL);
- gtk_signal_connect (GTK_OBJECT (scale_data), "value_changed",
- GTK_SIGNAL_FUNC (gimp_int_adjustment_update),
- &rvals.amplitude);
-
- gtk_widget_show (frame);
- gtk_widget_show (table);
-
- gtk_widget_show (main_vbox);
- gtk_widget_show (dlg);
-
- gtk_main ();
- gdk_flush ();
-
- return rpint.run;
- }
-
- static GimpTile *
- ripple_pixel (GimpDrawable *drawable,
- GimpTile *tile,
- gint x1,
- gint y1,
- gint x2,
- gint y2,
- gint x,
- gint y,
- gint *row,
- gint *col,
- guchar *pixel)
- {
- static guchar empty_pixel[4] = {0, 0, 0, 0};
-
- guchar *data;
- gint b;
-
- if (x >= x1 && y >= y1 && x < x2 && y < y2)
- {
- if ((x >> 6 != *col) || (y >> 6 != *row))
- {
- *col = x / 64;
- *row = y / 64;
- if (tile)
- gimp_tile_unref (tile, FALSE);
- tile = gimp_drawable_get_tile (drawable, FALSE, *row, *col);
- gimp_tile_ref (tile);
- }
-
- data = tile->data + tile->bpp * (tile->ewidth * (y % 64) + (x % 64));
- }
- else
- data = empty_pixel;
-
- for (b = 0; b < drawable->bpp; b++)
- pixel[b] = data[b];
-
- return tile;
- }
-
-
- /* Ripple interface functions */
-
- static void
- ripple_ok_callback (GtkWidget *widget,
- gpointer data)
- {
- rpint.run = TRUE;
-
- gtk_widget_destroy (GTK_WIDGET (data));
- }
-
- static guchar
- averagetwo (gdouble location,
- guchar *v)
- {
- location = fmod(location, 1.0);
-
- return (guchar) ((1.0 - location) * v[0] + location * v[1]);
- }
-
- static guchar
- averagefour (gdouble location,
- guchar *v)
- {
- location = fmod(location, 1.0);
-
- return ((1.0 - location) * (v[0] + v[2]) + location * (v[1] + v[3]))/2;
- }
-
- static gdouble
- displace_amount (gint location)
- {
- switch (rvals.waveform)
- {
- case SINE:
- return rvals.amplitude*sin(location*(2*G_PI)/(double)rvals.period);
- case SAWTOOTH:
- return floor (rvals.amplitude *
- (fabs ((((location%rvals.period) /
- (double)rvals.period) * 4) - 2) - 1));
- }
-
- return 0;
- }
-