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* CPU usage plugin to lxpanel
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* Copyright (c) 2008 LxDE Developers, see the file AUTHORS for details.
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* Copyright (C) 2004 by Alexandre Pereira da Silva <alexandre.pereira@poli.usp.br>
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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 2 of the License, or
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* (at your option) any later version.
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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 GNU
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* General Public License for more details.
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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, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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/*A little bug fixed by Mykola <mykola@2ka.mipt.ru>:) */
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#include <sys/sysinfo.h>
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#include <glib/gi18n.h>
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typedef unsigned long long CPUTick; /* Value from /proc/stat */
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typedef float CPUSample; /* Saved CPU utilization value as 0.0..1.0 */
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CPUTick u, n, s, i; /* User, nice, system, idle */
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/* Private context for CPU plugin. */
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GdkColor foreground_color; /* Foreground color for drawing area */
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GtkWidget * da; /* Drawing area */
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cairo_surface_t * pixmap; /* Pixmap to be drawn on drawing area */
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guint timer; /* Timer for periodic update */
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CPUSample * stats_cpu; /* Ring buffer of CPU utilization values */
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unsigned int ring_cursor; /* Cursor for ring buffer */
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int pixmap_width; /* Width of drawing area pixmap; also size of ring buffer; does not include border size */
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int pixmap_height; /* Height of drawing area pixmap; does not include border size */
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struct cpu_stat previous_cpu_stat; /* Previous value of cpu_stat */
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static void redraw_pixmap(CPUPlugin * c);
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static gboolean cpu_update(CPUPlugin * c);
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static gboolean configure_event(GtkWidget * widget, GdkEventConfigure * event, CPUPlugin * c);
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static gboolean expose_event(GtkWidget * widget, GdkEventExpose * event, CPUPlugin * c);
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static int cpu_constructor(Plugin * p, char ** fp);
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static void cpu_destructor(Plugin * p);
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/* Redraw after timer callback or resize. */
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static void redraw_pixmap(CPUPlugin * c)
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cairo_t * cr = cairo_create(c->pixmap);
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cairo_set_line_width (cr, 1.0);
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cairo_rectangle(cr, 0, 0, c->pixmap_width, c->pixmap_height);
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gdk_cairo_set_source_color(cr, &c->da->style->black);
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/* Recompute pixmap. */
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unsigned int drawing_cursor = c->ring_cursor;
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gdk_cairo_set_source_color(cr, &c->foreground_color);
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for (i = 0; i < c->pixmap_width; i++)
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/* Draw one bar of the CPU usage graph. */
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if (c->stats_cpu[drawing_cursor] != 0.0)
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cairo_move_to(cr, i + 0.5, c->pixmap_height);
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cairo_line_to(cr, i + 0.5, c->pixmap_height - c->stats_cpu[drawing_cursor] * c->pixmap_height);
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/* Increment and wrap drawing cursor. */
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if (drawing_cursor >= c->pixmap_width)
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check_cairo_status(cr);
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gtk_widget_queue_draw(c->da);
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/* Periodic timer callback. */
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static gboolean cpu_update(CPUPlugin * c)
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if ((c->stats_cpu != NULL) && (c->pixmap != NULL))
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/* Open statistics file and scan out CPU usage. */
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FILE * stat = fopen("/proc/stat", "r");
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int fscanf_result = fscanf(stat, "cpu %llu %llu %llu %llu", &cpu.u, &cpu.n, &cpu.s, &cpu.i);
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/* Ensure that fscanf succeeded. */
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if (fscanf_result == 4)
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/* Compute delta from previous statistics. */
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struct cpu_stat cpu_delta;
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cpu_delta.u = cpu.u - c->previous_cpu_stat.u;
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cpu_delta.n = cpu.n - c->previous_cpu_stat.n;
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cpu_delta.s = cpu.s - c->previous_cpu_stat.s;
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cpu_delta.i = cpu.i - c->previous_cpu_stat.i;
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/* Copy current to previous. */
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memcpy(&c->previous_cpu_stat, &cpu, sizeof(struct cpu_stat));
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/* Compute user+nice+system as a fraction of total.
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* Introduce this sample to ring buffer, increment and wrap ring buffer cursor. */
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float cpu_uns = cpu_delta.u + cpu_delta.n + cpu_delta.s;
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c->stats_cpu[c->ring_cursor] = cpu_uns / (cpu_uns + cpu_delta.i);
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if (c->ring_cursor >= c->pixmap_width)
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/* Redraw with the new sample. */
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/* Handler for configure_event on drawing area. */
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static gboolean configure_event(GtkWidget * widget, GdkEventConfigure * event, CPUPlugin * c)
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/* Allocate pixmap and statistics buffer without border pixels. */
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int new_pixmap_width = widget->allocation.width - BORDER_SIZE * 2;
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int new_pixmap_height = widget->allocation.height - BORDER_SIZE * 2;
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if ((new_pixmap_width > 0) && (new_pixmap_height > 0))
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/* If statistics buffer does not exist or it changed size, reallocate and preserve existing data. */
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if ((c->stats_cpu == NULL) || (new_pixmap_width != c->pixmap_width))
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CPUSample * new_stats_cpu = g_new0(typeof(*c->stats_cpu), new_pixmap_width);
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if (c->stats_cpu != NULL)
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if (new_pixmap_width > c->pixmap_width)
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/* New allocation is larger.
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* Introduce new "oldest" samples of zero following the cursor. */
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memcpy(&new_stats_cpu[0],
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&c->stats_cpu[0], c->ring_cursor * sizeof(CPUSample));
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memcpy(&new_stats_cpu[new_pixmap_width - c->pixmap_width + c->ring_cursor],
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&c->stats_cpu[c->ring_cursor], (c->pixmap_width - c->ring_cursor) * sizeof(CPUSample));
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else if (c->ring_cursor <= new_pixmap_width)
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/* New allocation is smaller, but still larger than the ring buffer cursor.
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* Discard the oldest samples following the cursor. */
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memcpy(&new_stats_cpu[0],
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&c->stats_cpu[0], c->ring_cursor * sizeof(CPUSample));
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memcpy(&new_stats_cpu[c->ring_cursor],
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&c->stats_cpu[c->pixmap_width - new_pixmap_width + c->ring_cursor], (new_pixmap_width - c->ring_cursor) * sizeof(CPUSample));
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/* New allocation is smaller, and also smaller than the ring buffer cursor.
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* Discard all oldest samples following the ring buffer cursor and additional samples at the beginning of the buffer. */
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memcpy(&new_stats_cpu[0],
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&c->stats_cpu[c->ring_cursor - new_pixmap_width], new_pixmap_width * sizeof(CPUSample));
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g_free(c->stats_cpu);
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c->stats_cpu = new_stats_cpu;
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/* Allocate or reallocate pixmap. */
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c->pixmap_width = new_pixmap_width;
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c->pixmap_height = new_pixmap_height;
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cairo_surface_destroy(c->pixmap);
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c->pixmap = cairo_image_surface_create(CAIRO_FORMAT_RGB24, c->pixmap_width, c->pixmap_height);
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check_cairo_surface_status(&c->pixmap);
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/* Redraw pixmap at the new size. */
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/* Handler for expose_event on drawing area. */
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static gboolean expose_event(GtkWidget * widget, GdkEventExpose * event, CPUPlugin * c)
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/* Draw the requested part of the pixmap onto the drawing area.
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* Translate it in both x and y by the border size. */
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if (c->pixmap != NULL)
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cairo_t * cr = gdk_cairo_create(widget->window);
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gdk_cairo_region(cr, event->region);
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gdk_cairo_set_source_color(cr, &c->da->style->black);
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cairo_set_source_surface(cr, c->pixmap,
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BORDER_SIZE, BORDER_SIZE);
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check_cairo_status(cr);
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/* Plugin constructor. */
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static int cpu_constructor(Plugin * p, char ** fp)
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/* Allocate plugin context and set into Plugin private data pointer. */
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CPUPlugin * c = g_new0(CPUPlugin, 1);
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/* Allocate top level widget and set into Plugin widget pointer. */
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p->pwid = gtk_event_box_new();
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gtk_container_set_border_width(GTK_CONTAINER(p->pwid), 1);
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GTK_WIDGET_SET_FLAGS(p->pwid, GTK_NO_WINDOW);
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/* Allocate drawing area as a child of top level widget. Enable button press events. */
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c->da = gtk_drawing_area_new();
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gtk_widget_set_size_request(c->da, 40, PANEL_HEIGHT_DEFAULT);
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gtk_widget_add_events(c->da, GDK_BUTTON_PRESS_MASK);
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gtk_container_add(GTK_CONTAINER(p->pwid), c->da);
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/* Clone a graphics context and set "green" as its foreground color.
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* We will use this to draw the graph. */
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gdk_color_parse("green", &c->foreground_color);
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/* Connect signals. */
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g_signal_connect(G_OBJECT(c->da), "configure_event", G_CALLBACK(configure_event), (gpointer) c);
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g_signal_connect(G_OBJECT(c->da), "expose_event", G_CALLBACK(expose_event), (gpointer) c);
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g_signal_connect(c->da, "button-press-event", G_CALLBACK(plugin_button_press_event), p);
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/* Show the widget. Connect a timer to refresh the statistics. */
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gtk_widget_show(c->da);
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c->timer = g_timeout_add(1500, (GSourceFunc) cpu_update, (gpointer) c);
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/* Plugin destructor. */
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static void cpu_destructor(Plugin * p)
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CPUPlugin * c = (CPUPlugin *) p->priv;
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/* Disconnect the timer. */
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g_source_remove(c->timer);
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/* Deallocate memory. */
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cairo_surface_destroy(c->pixmap);
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g_free(c->stats_cpu);
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/* Plugin descriptor. */
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PluginClass cpu_plugin_class = {
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PLUGINCLASS_VERSIONING,
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name : N_("CPU Usage Monitor"),
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description : N_("Display CPU usage"),
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constructor : cpu_constructor,
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destructor : cpu_destructor,
added
removed
src/plugins/cpu/cpu.c
