diff options
Diffstat (limited to 'doc/tutorial/src')
| -rw-r--r-- | doc/tutorial/src/.gitignore | 8 | ||||
| -rw-r--r-- | doc/tutorial/src/README | 66 | ||||
| -rw-r--r-- | doc/tutorial/src/circle.c | 22 | ||||
| -rw-r--r-- | doc/tutorial/src/include/cairo-tutorial-gtk.h | 133 | ||||
| -rw-r--r-- | doc/tutorial/src/include/cairo-tutorial-pdf.h | 74 | ||||
| -rw-r--r-- | doc/tutorial/src/include/cairo-tutorial-png.h | 74 | ||||
| -rw-r--r-- | doc/tutorial/src/include/cairo-tutorial-xlib.h | 251 | ||||
| -rw-r--r-- | doc/tutorial/src/include/cairo-tutorial.h | 40 | ||||
| -rw-r--r-- | doc/tutorial/src/lca.c | 32 | ||||
| -rw-r--r-- | doc/tutorial/src/singular.c | 162 | ||||
| -rw-r--r-- | doc/tutorial/src/twin.c | 39 |
11 files changed, 0 insertions, 901 deletions
diff --git a/doc/tutorial/src/.gitignore b/doc/tutorial/src/.gitignore deleted file mode 100644 index 68af59e73..000000000 --- a/doc/tutorial/src/.gitignore +++ /dev/null @@ -1,8 +0,0 @@ -*-gtk -*-pdf -*-png -*-xlib -*.pdf -*.png -*.o -*~ diff --git a/doc/tutorial/src/README b/doc/tutorial/src/README deleted file mode 100644 index a2738da4e..000000000 --- a/doc/tutorial/src/README +++ /dev/null @@ -1,66 +0,0 @@ -Welcome to the cairo tutorial: - -+--------------------------------+ -| How to Recognize Ugly Graphics | -|(and what you can do about them)| -+--------------------------------+ - -This directory is your personal playground for following along with -the examples. In order for you to make use of these files you will -need to have cairo and its header files installed. You can find -instructions for doing this at: - - http://cairographics.org/tutorial - -Notice that there are a few .c files in this directory. - -You should start out by just typing "make" which will turn each .c -file into several different programs. Go ahead and run each of the -programs and see what they do. Some of them will open up new X windows -while others will simply write their output to files (such .png or -.pdf). - -After you play with those a bit, go ahead and take a look at the -contents of the .c files. You'll see that each file contains a draw() -function that does all of the drawing. - -You might be surprised to notice that there is no main() function in -any of the files. Instead, main is hidden away by means of -cairo-tutorial.h. This rather non-conventional style is used to allow -you to focus on the actual drawing code involved in using cairo, while -not having to worry about the setup semantics. We don't recommend that -you follow this style for real projects. - -As you follow along during the tutorial and get some ideas for things -to draw, you'll want to start making your own .c files. You can copy -an existing file or make your own by following this simple minimal -template: - - #include "cairo-tutorial.h" - - static void - draw (cairo_t *cr, int width, int height) - { - /* Put your drawing code here. */ - } - -Any new file you create will automatically get picked up by the -Makefile so that "make" will compile your file into several different -programs, just like the existing examples. - -If you'd like to control the initial size of the output, you may -define WIDTH and HEIGHT before including cairo-tutorial.h like so: - - #define WIDTH 100 - #define HEIGHT 100 - - #include "cairo-tutorial.h" - -If you would like to change the set of cairo-backend target programs -that are compiled, you may edit the "all" target in the Makefile. - -Have fun! - --Carl Worth - -cworth@redhat.com diff --git a/doc/tutorial/src/circle.c b/doc/tutorial/src/circle.c deleted file mode 100644 index 6bd02e8ba..000000000 --- a/doc/tutorial/src/circle.c +++ /dev/null @@ -1,22 +0,0 @@ -#include "cairo-tutorial.h" - -static void -draw (cairo_t *cr, int width, int height) -{ - int radius; - - if (width < height) - radius = width/2 - 4; - else - radius = height/2 - 4; - - cairo_move_to (cr, width/2 + radius, height/2); - cairo_arc (cr, width/2, height/2, radius, - 0.0, 2 * M_PI); - - cairo_set_source_rgb (cr, 0.6, 0.8, 1.0); - cairo_fill_preserve (cr); - - cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); - cairo_stroke (cr); -} diff --git a/doc/tutorial/src/include/cairo-tutorial-gtk.h b/doc/tutorial/src/include/cairo-tutorial-gtk.h deleted file mode 100644 index 60516a356..000000000 --- a/doc/tutorial/src/include/cairo-tutorial-gtk.h +++ /dev/null @@ -1,133 +0,0 @@ -/* cairo-tutorial-gtk.h - a tutorial framework for cairo with gtk+ - * - * Copyright © 2005, Carl Worth - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. - */ - -#include <gtk/gtk.h> -#include <gdk/gdkkeysyms.h> - -#include <cairo.h> - -#ifndef WIDTH -#define WIDTH 400 -#endif - -#ifndef HEIGHT -#define HEIGHT 400 -#endif - -static void -draw (cairo_t *cr, int width, int height); - -#if ! GTK_CHECK_VERSION(2,7,0) -/* copied from gtk+/gdk/gdkcairo.c and gtk+/gdk/x11/gdkdrawable-x11.c - * gdk_cairo_create() which is available in 2.7.0 and later. - */ -static cairo_t * -gdk_cairo_create (GdkDrawable *drawable) -{ - int width, height; - cairo_t *cr = NULL; - cairo_surface_t *surface = NULL; - GdkVisual *visual = gdk_drawable_get_visual (drawable); - - gdk_drawable_get_size (drawable, &width, &height); - if (visual) - surface = cairo_xlib_surface_create (GDK_DRAWABLE_XDISPLAY (drawable), - GDK_DRAWABLE_XID (drawable), - GDK_VISUAL_XVISUAL (visual), - width, height); - else if (gdk_drawable_get_depth (drawable) == 1) - surface = cairo_xlib_surface_create_for_bitmap - (GDK_PIXMAP_XDISPLAY (drawable), - GDK_PIXMAP_XID (drawable), - GDK_SCREEN_XSCREEN (gdk_drawable_get_screen (drawable)), - width, height); - else { - g_warning ("Using Cairo rendering requires the drawable argument to\n" - "have a specified colormap. All windows have a colormap,\n" - "however, pixmaps only have colormap by default if they\n" - "were created with a non-NULL window argument. Otherwise\n" - "a colormap must be set on them with " - "gdk_drawable_set_colormap"); - return NULL; - } - if (surface) { - cr = cairo_create (surface); - cairo_surface_destroy (surface); - } - return cr; -} -#endif - -static gboolean -handle_expose (GtkWidget *widget, - GdkEventExpose *event, - gpointer data) -{ - cairo_t *cr; - - cr = gdk_cairo_create (widget->window); - - draw (cr, widget->allocation.width, widget->allocation.height); - - cairo_destroy (cr); - - return FALSE; -} - -static gboolean -handle_key_press (GtkWidget *widget, - GdkEventKey *event, - gpointer data) -{ - if ((event->keyval == GDK_Q || - event->keyval == GDK_q) && (event->state & GDK_CONTROL_MASK)) - gtk_main_quit (); - - return FALSE; -} - -int -main (int argc, char **argv) -{ - GtkWidget *window, *drawing_area; - - gtk_init (&argc, &argv); - - window = gtk_window_new (GTK_WINDOW_TOPLEVEL); - - gtk_window_set_default_size (GTK_WINDOW (window), WIDTH, HEIGHT); - gtk_window_set_title (GTK_WINDOW (window), "cairo demo"); - - g_signal_connect (window, "destroy", - G_CALLBACK (gtk_main_quit), NULL); - - drawing_area = gtk_drawing_area_new (); - gtk_container_add (GTK_CONTAINER (window), drawing_area); - - g_signal_connect (drawing_area, "expose-event", - G_CALLBACK (handle_expose), NULL); - - g_signal_connect (window, "key-press-event", - G_CALLBACK (handle_key_press), NULL); - - gtk_widget_show_all (window); - - gtk_main (); - - return 0; -} diff --git a/doc/tutorial/src/include/cairo-tutorial-pdf.h b/doc/tutorial/src/include/cairo-tutorial-pdf.h deleted file mode 100644 index 00d0f188e..000000000 --- a/doc/tutorial/src/include/cairo-tutorial-pdf.h +++ /dev/null @@ -1,74 +0,0 @@ -/* cairo-tutorial-png.h - a tutorial framework for cairo to write a PNG image - * - * Copyright © 2005, Carl Worth - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. - */ - -#include <cairo.h> -#include <cairo-pdf.h> - -#include <stdio.h> -#include <stdlib.h> -#include <assert.h> -#include <string.h> - -#ifndef WIDTH -#define WIDTH 400 -#endif - -#ifndef HEIGHT -#define HEIGHT 400 -#endif - -static void -draw (cairo_t *cr, int width, int height); - -int -main (int argc, char **argv) -{ - cairo_surface_t *surface; - cairo_t *cr; - char *filename, *dash; - - filename = strdup (argv[0]); - assert (filename != NULL); - - dash = strrchr (filename, '-'); - - if (strcmp (dash, "-pdf") == 0) { - *dash = '.'; - } else { - char *new_filename; - new_filename = malloc (strlen (filename) + 5); - sprintf (new_filename, "%s.pdf", filename); - free (filename); - filename = new_filename; - } - - surface = cairo_pdf_surface_create (filename, WIDTH, HEIGHT); - - cr = cairo_create (surface); - - draw (cr, WIDTH, HEIGHT); - - cairo_show_page (cr); - - cairo_surface_destroy (surface); - cairo_destroy (cr); - - free (filename); - - return 0; -} diff --git a/doc/tutorial/src/include/cairo-tutorial-png.h b/doc/tutorial/src/include/cairo-tutorial-png.h deleted file mode 100644 index 428baf294..000000000 --- a/doc/tutorial/src/include/cairo-tutorial-png.h +++ /dev/null @@ -1,74 +0,0 @@ -/* cairo-tutorial-png.h - a tutorial framework for cairo to write a PNG image - * - * Copyright © 2005, Carl Worth - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. - */ - -#include <cairo.h> - -#include <stdio.h> -#include <stdlib.h> -#include <assert.h> -#include <string.h> - -#ifndef WIDTH -#define WIDTH 400 -#endif - -#ifndef HEIGHT -#define HEIGHT 400 -#endif - -static void -draw (cairo_t *cr, int width, int height); - -int -main (int argc, char **argv) -{ - cairo_surface_t *surface; - cairo_t *cr; - char *filename, *dash; - - surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, - WIDTH, HEIGHT); - - cr = cairo_create (surface); - - draw (cr, WIDTH, HEIGHT); - - filename = strdup (argv[0]); - assert (filename != NULL); - - dash = strrchr (filename, '-'); - - if (strcmp (dash, "-png") == 0) { - *dash = '.'; - } else { - char *new_filename; - new_filename = malloc (strlen (filename) + 5); - sprintf (new_filename, "%s.png", filename); - free (filename); - filename = new_filename; - } - - cairo_surface_write_to_png (surface, filename); - - free (filename); - - cairo_surface_destroy (surface); - cairo_destroy (cr); - - return 0; -} diff --git a/doc/tutorial/src/include/cairo-tutorial-xlib.h b/doc/tutorial/src/include/cairo-tutorial-xlib.h deleted file mode 100644 index 5e78d0354..000000000 --- a/doc/tutorial/src/include/cairo-tutorial-xlib.h +++ /dev/null @@ -1,251 +0,0 @@ -/* cairo-tutorial-xlib.h - a tutorial framework for cairo with xlib - * - * Copyright © 2005, Keith Packard - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. - */ - -#include <stdio.h> -#include <stdlib.h> -#include <ctype.h> -#include <strings.h> -#include <X11/Xos.h> -#include <X11/Xlib.h> -#include <X11/Xutil.h> -#include <X11/Xatom.h> -#include <cairo.h> -#include <cairo-xlib.h> - -#ifndef WIDTH -#define WIDTH 400 -#endif - -#ifndef HEIGHT -#define HEIGHT 400 -#endif - -#ifndef DEFAULT_VISUAL -#define DEFAULT_VISUAL 0 -#endif - -static void -Usage (char *program) -{ - fprintf (stderr, "Usage: %s\n", program); - fprintf (stderr, "\t-display <display-name>\n"); - fprintf (stderr, "\t-geometry <geometry>\n"); - exit (1); -} - -char *dpy_name; -VisualID vid = DEFAULT_VISUAL; -Colormap colormap; -Visual *visual; -int depth; -unsigned int width = WIDTH, height = HEIGHT; -Window win; -Pixmap pix; -GC gc; - -static void -draw (cairo_t *cr, int width, int height); - -static void -draw_to_pixmap (Display *dpy, Pixmap pix) -{ - cairo_surface_t *surface; - cairo_t *cr; - - surface = cairo_xlib_surface_create (dpy, pix, visual, - width, height); - cr = cairo_create (surface); - - draw (cr, width, height); - - cairo_destroy (cr); - cairo_surface_destroy (surface); -} - -static void -handle_configure (Display *dpy, XConfigureEvent *cev) -{ - width = cev->width; - height = cev->height; - - XFreePixmap(dpy, pix); - pix = XCreatePixmap(dpy, win, width, height, depth); - XFillRectangle(dpy, pix, gc, 0, 0, width, height); - draw_to_pixmap (dpy, pix); -} - -static void -handle_expose (Display *dpy, XExposeEvent *eev) -{ - XCopyArea (dpy, pix, win, gc, - eev->x, eev->y, - eev->width, eev->height, - eev->x, eev->y); -} - -int -main (argc, argv) - int argc; - char **argv; -{ - Display *dpy; - Window root = 0; - char **init_argv = argv; - XSetWindowAttributes attr; - int scr; - int x = 0, y = 0; - int geometryMask; - int border_width = 1; - XSizeHints sizeHints; - XWMHints wmHints; - XClassHint classHints; - XEvent ev; - XEvent eev; - int HasExpose = 0; - int sync = 0; - XTextProperty wm_name, icon_name; - Atom wm_delete_window; - unsigned long gc_mask; - XGCValues gcv; - char quit_string[10]; - unsigned long window_mask; - int has_colormap = 0; - - wm_name.value = (unsigned char *) argv[0]; - wm_name.encoding = XA_STRING; - wm_name.format = 8; - wm_name.nitems = strlen (argv[0]) + 1; - icon_name = wm_name; - gc_mask = 0; - while (*++argv) { - if (!strcmp (*argv, "-display")) - dpy_name = *++argv; - else if (!strcmp (*argv, "-visual")) - vid = strtol(*++argv, NULL, 0); - else if (!strcmp (*argv, "-geometry")) - geometryMask = XParseGeometry (*++argv, &x, &y, &width, &height); - else if (!strcmp (*argv, "-sync")) - sync = 1; - else if (!strcmp (*argv, "-bw")) - border_width = strtol(*++argv, NULL, 0); - else if (!strcmp (*argv, "-root")) - root = strtol (*++argv, NULL, 0); - else - Usage (*init_argv); - } - sizeHints.flags = 0; - wmHints.flags = InputHint; - wmHints.input = True; - classHints.res_name = init_argv[0]; - classHints.res_class = init_argv[0]; - dpy = XOpenDisplay (dpy_name); - if (!dpy) { - fprintf (stderr, "Error: failed to open display: %s\n", - XDisplayName (dpy_name)); - exit (1); - } - if (sync) - XSynchronize (dpy, sync); - scr = DefaultScreen (dpy); - if (!root) - root = RootWindow (dpy, scr); - window_mask = CWBackPixel|CWBorderPixel|CWEventMask; - if (!has_colormap) - colormap = DefaultColormap (dpy, scr); - else - { - window_mask |= CWColormap; - attr.colormap = colormap; - } - visual = DefaultVisual (dpy, scr); - depth = DefaultDepth (dpy, scr); - if (vid) - { - XVisualInfo vi, *vi_ret; - int n; - - vi.visualid = vid; - vi.screen = scr; - vi_ret = XGetVisualInfo (dpy, VisualIDMask|VisualScreenMask, - &vi, &n); - if (vi_ret) - { - visual = vi_ret->visual; - if (!has_colormap) - { - colormap = XCreateColormap (dpy, root, visual, AllocNone); - window_mask |= CWColormap; - attr.colormap = colormap; - } - depth = vi_ret->depth; - } - } - attr.background_pixel = WhitePixel (dpy, scr); - attr.border_pixel = 0; - attr.event_mask = ExposureMask|KeyPressMask|KeyReleaseMask|StructureNotifyMask; - wm_delete_window = XInternAtom(dpy, "WM_DELETE_WINDOW", False); - win = XCreateWindow (dpy, root, x, y, width, height, border_width, - depth, InputOutput, - visual, - window_mask, - &attr); - pix = XCreatePixmap (dpy, win, width, height, depth); - gcv.foreground = WhitePixel (dpy, scr); - gc = XCreateGC (dpy, pix, GCForeground, &gcv); - XFillRectangle(dpy, pix, gc, 0, 0, width, height); - draw_to_pixmap (dpy, pix); - XSetWMProperties (dpy, win, - &wm_name, &icon_name, - init_argv, argc, - &sizeHints, &wmHints, 0); - XSetWMProtocols (dpy, win, &wm_delete_window, 1); - XMapWindow (dpy, win); - for (;;) { - XNextEvent (dpy, &ev); - if (HasExpose && ev.type != Expose) { - HasExpose = 0; - handle_expose (dpy, &eev.xexpose); - } - switch (ev.type) { - case ConfigureNotify: - handle_configure (dpy, &ev.xconfigure); - break; - case Expose: - if (QLength(dpy)) { - eev = ev; - HasExpose = 1; - } else if (ev.xexpose.count == 0) { - handle_expose (dpy, &ev.xexpose); - } - break; - case KeyPress: - if (XLookupString ((XKeyEvent *) &ev, quit_string, sizeof (quit_string), 0, 0) == 1) { - switch (quit_string[0]) { - case 'q': - exit (0); - case 'c': - XClearArea (dpy, ev.xkey.window, 0, 0, 0, 0, True); - break; - } - } - break; - case ClientMessage: - exit (0); - } - } -} diff --git a/doc/tutorial/src/include/cairo-tutorial.h b/doc/tutorial/src/include/cairo-tutorial.h deleted file mode 100644 index ec738e915..000000000 --- a/doc/tutorial/src/include/cairo-tutorial.h +++ /dev/null @@ -1,40 +0,0 @@ -/* cairo-tutorial-gtk.h - a tutorial framework for cairo - * - * Copyright © 2005, Carl Worth - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * - * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA. - */ - -#include <cairo.h> -#include <math.h> - -/* The application program may override these before including - * cairo-tutorial.h in order to get a window of a different size. */ -#ifndef WIDTH -#define WIDTH 400 -#endif - -#ifndef HEIGHT -#define HEIGHT 400 -#endif - -#ifdef CAIRO_TUTORIAL_GTK -#include "cairo-tutorial-gtk.h" -#elif CAIRO_TUTORIAL_XLIB -#include "cairo-tutorial-xlib.h" -#elif CAIRO_TUTORIAL_PDF -#include "cairo-tutorial-pdf.h" -#elif CAIRO_TUTORIAL_PNG -#include "cairo-tutorial-png.h" -#endif diff --git a/doc/tutorial/src/lca.c b/doc/tutorial/src/lca.c deleted file mode 100644 index 0b131afaf..000000000 --- a/doc/tutorial/src/lca.c +++ /dev/null @@ -1,32 +0,0 @@ -#define WIDTH 750 -#define HEIGHT 360 - -#include "cairo-tutorial.h" - -static void -draw (cairo_t *cr, int width, int height) -{ - cairo_save (cr); - - cairo_translate (cr, 60, 60); - cairo_scale (cr, 3, 3); - - cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND); - cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND); - cairo_set_line_width (cr, 20); - - /* L */ - cairo_move_to (cr, 0, 0); - cairo_line_to (cr, 0, 80); - cairo_line_to (cr, 50, 80); - - /* C */ - cairo_move_to (cr, 110 + 40 * cos (M_PI / 3), 40 + 40 * sin(M_PI / 3)); - cairo_arc (cr, 110, 40, 40, M_PI / 3, -M_PI / 3); - - /* A */ - cairo_move_to (cr, 160, 80); - cairo_curve_to (cr, 160, -30, 210, -30, 210, 80); - - cairo_stroke (cr); -} diff --git a/doc/tutorial/src/singular.c b/doc/tutorial/src/singular.c deleted file mode 100644 index 958b2b047..000000000 --- a/doc/tutorial/src/singular.c +++ /dev/null @@ -1,162 +0,0 @@ -/** - * Uses Singular values of transformation matrix to find the length of the - * major and minor axes of the scaled pen. - * - * Put this file in cairo/doc/tutorial/src and type "make" - */ - -#define WIDTH 300 -#define HEIGHT 300 - -#include "cairo-tutorial.h" - -#include <math.h> - -/* - * Finds the singular values of the non-translation part of matrix. - * - * Let M be the cairo transformation matrix in question: - * - * ⌈xx xy⌉ - * M = |yx yy| - * ⌊x0 y0⌋ - * - * The non-translation part is: - * - * A = ⌈xx xy⌉ - * ⌊yx yy⌋ - * - * The non-zero singular values of A are the square roots of the non-zero - * eigenvalues of A⁺ A, where A⁺ is A-transpose. - * - * A⁺ A = ⌈xx yx⌉⌈xx xy⌉ = ⌈xx²+yx² xx*xy+yx*yy⌉ - * ⌊xy yy⌋⌊yx yy⌋ ⌊xx*xy+yx*yy xy²+yy²⌋ - * - * Name those: - * - * B = A⁺ A = ⌈a k⌉ - * ⌊k b⌋ - * - * The eigenvalues of B satisfy: - * - * λ² - (a+b).λ + a.b - k² = 0 - * - * The eigenvalues are: - * __________________ - * (a+b) ± √(a+b)² - 4(a.b-k²) - * λ = --------------------------- - * 2 - * that simplifies to: - * _______________ - * λ = (a+b)/2 ± √((a-b)/2)² + k² - * - * And the Singular values are the root of λs. - * - */ -static void -get_singular_values (const cairo_matrix_t *matrix, - double *major, - double *minor) -{ - double xx = matrix->xx, xy = matrix->xy; - double yx = matrix->yx, yy = matrix->yy; - - double a = xx*xx+yx*yx; - double b = xy*xy+yy*yy; - double k = xx*xy+yx*yy; - - double f = (a+b) * .5; - double g = (a-b) * .5; - double delta = sqrt (g*g + k*k); - - if (major) - *major = sqrt (f + delta); - if (minor) - *minor = sqrt (f - delta); -} - -/* - * Finds the length of the major and minor axes of the pen for a cairo_t, - * identified by the current transformation matrix and line width. - * - * Returned values are in device units. - */ -static void -get_pen_axes (cairo_t *cr, - double *major, - double *minor) -{ - double width; - cairo_matrix_t matrix; - - width = cairo_get_line_width (cr); - cairo_get_matrix (cr, &matrix); - - get_singular_values (&matrix, major, minor); - - if (major) - *major *= width; - if (minor) - *minor *= width; -} - -static void -draw (cairo_t *cr, int width, int height) -{ - double major_width, minor_width; - - /* clear background */ - cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */ - cairo_paint (cr); - -#define W width -#define H height -#define B ((width+height)/16) - - /* the spline we want to stroke */ - cairo_move_to (cr, W-B, B); - cairo_curve_to (cr, -W, B, - 2*W, H-B, - B, H-B); - - /* the effect is show better with round caps */ - cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND); - - /* set the skewed pen */ - cairo_rotate (cr, +.7); - cairo_scale (cr, .5, 2.); - cairo_rotate (cr, -.7); - cairo_set_line_width (cr, B); - - get_pen_axes (cr, &major_width, &minor_width); - - /* stroke with "major" pen in translucent red */ - cairo_save (cr); - cairo_identity_matrix (cr); - cairo_set_line_width (cr, major_width); - cairo_set_source_rgba (cr, 1.0, 0.0, 0.0, .9); - cairo_stroke_preserve (cr); - cairo_restore (cr); - - /* stroke with skewed pen in translucent black */ - cairo_set_source_rgba (cr, 0.0, 0.0, 0.0, .9); - cairo_stroke_preserve (cr); - - /* stroke with "minor" pen in translucent yellow */ - cairo_save (cr); - cairo_identity_matrix (cr); - cairo_set_line_width (cr, minor_width); - cairo_set_source_rgba (cr, 1.0, 1.0, 0.0, .9); - cairo_stroke_preserve (cr); - cairo_restore (cr); - - /* stroke with hairline in black */ - cairo_save (cr); - cairo_identity_matrix (cr); - cairo_set_line_width (cr, 1); - cairo_set_source_rgb (cr, 0.0, 0.0, 0.0); - cairo_stroke_preserve (cr); - cairo_restore (cr); - - cairo_new_path (cr); -} diff --git a/doc/tutorial/src/twin.c b/doc/tutorial/src/twin.c deleted file mode 100644 index 14347bac2..000000000 --- a/doc/tutorial/src/twin.c +++ /dev/null @@ -1,39 +0,0 @@ -/** - * Put this file in cairo/doc/tutorial/src and type "make" - */ - -#define WIDTH 1350 -#define HEIGHT 900 - -#include "cairo-tutorial.h" - - -static void -draw (cairo_t *cr, int width, int height) -{ - int i, j, h; - unsigned char s[2] = {0, 0}; - - /* clear background */ - cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */ - cairo_paint (cr); - - cairo_set_source_rgb (cr, 0, 0, 0); - cairo_select_font_face (cr, - "@cairo:", - CAIRO_FONT_SLANT_NORMAL, - CAIRO_FONT_WEIGHT_NORMAL); - - h = 2; - for (i = 8; i < 48; i >= 24 ? i+=3 : i++) { - cairo_set_font_size (cr, i); - for (j = 33; j < 128; j++) { - if (j == 33 || (j == 80 && i > 24)) { - h += i + 2; - cairo_move_to (cr, 10, h); - } - s[0] = j; - cairo_show_text (cr, (const char *) s); - } - } -} |