#include <cstring>

#include <cmath>

#include <cstdio>

#include "widget-sizes.h"

#include "desktop-widget.h"

#include "ruler.h"

#include "unit-constants.h"

#include "round.h"

#include <glibmm/i18n.h>

#define GTK_PARAM_READWRITE G_PARAM_READWRITE|G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB

#define MINIMUM_INCR 5

#define MAXIMUM_SUBDIVIDE 5

#define MAXIMUM_SCALES 10

#define ROUND(x) ((int) ((x) + 0.5))

struct _SPRulerPrivate

{

GtkOrientation orientation;

SPRulerMetric *metric;

#if GTK_CHECK_VERSION(3,0,0)

cairo_surface_t *backing_store;

#else

GdkPixmap *backing_store;

#endif

gint slider_size;

gint xsrc;

gint ysrc;

gdouble lower; /* The upper limit of the ruler (in points) */

gdouble upper; /* The lower limit of the ruler */

gdouble position; /* The position of the mark on the ruler */

gdouble max_size; /* The maximum size of the ruler */

};

enum {

PROP_0,

PROP_ORIENTATION,

PROP_LOWER,

PROP_UPPER,

PROP_POSITION,

PROP_MAX_SIZE,

PROP_METRIC

};

static void sp_ruler_set_property (GObject *object,

guint prop_id,

const GValue *value,

GParamSpec *pspec);

static void sp_ruler_get_property (GObject *object,

guint prop_id,

GValue *value,

GParamSpec *pspec);

static void sp_ruler_realize (GtkWidget *widget);

static void sp_ruler_unrealize (GtkWidget *widget);

static void sp_ruler_size_request (GtkWidget *widget,

GtkRequisition *requisition);

#if GTK_CHECK_VERSION(3,0,0)

static void sp_ruler_get_preferred_width (GtkWidget *widget,

gint *minimal_width,

gint *natural_width);

static void sp_ruler_get_preferred_height (GtkWidget *widget,

gint *minimal_height,

gint *natural_height);

#endif

static void sp_ruler_size_allocate (GtkWidget *widget,

GtkAllocation *allocation);

static gboolean sp_ruler_motion_notify (GtkWidget *widget,

GdkEventMotion *event);

static gboolean sp_ruler_expose (GtkWidget *widget,

GdkEventExpose *event);

static void sp_ruler_make_pixmap (SPRuler *ruler);

static void sp_ruler_real_draw_ticks (SPRuler *ruler);

static void sp_ruler_real_draw_pos (SPRuler *ruler);

#define SP_RULER_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), SP_TYPE_RULER, SPRulerPrivate))

static SPRulerMetric const sp_ruler_metrics[] = {

// NOTE: the order of records in this struct must correspond to the SPMetric enum.

{const_cast<gchar*>("NONE"), const_cast<gchar*>(""), 1, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("millimeters"), const_cast<gchar*>("mm"), PX_PER_MM, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("centimeters"), const_cast<gchar*>("cm"), PX_PER_CM, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("inches"), const_cast<gchar*>("in"), PX_PER_IN, { 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 }, { 1, 2, 4, 8, 16 }},

{const_cast<gchar*>("feet"), const_cast<gchar*>("ft"), PX_PER_FT, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("points"), const_cast<gchar*>("pt"), PX_PER_PT, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("picas"), const_cast<gchar*>("pc"), PX_PER_PC, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("pixels"), const_cast<gchar*>("px"), PX_PER_PX, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

{const_cast<gchar*>("meters"), const_cast<gchar*>("m"), PX_PER_M, { 1, 2, 5, 10, 25, 50, 100, 250, 500, 1000 }, { 1, 5, 10, 50, 100 }},

};

G_DEFINE_TYPE_WITH_CODE (SPRuler, sp_ruler, GTK_TYPE_WIDGET,

G_IMPLEMENT_INTERFACE (GTK_TYPE_ORIENTABLE,

NULL))

static void

sp_ruler_class_init (SPRulerClass *klass)

{

GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);

gobject_class->set_property = sp_ruler_set_property;

gobject_class->get_property = sp_ruler_get_property;

widget_class->realize = sp_ruler_realize;

widget_class->unrealize = sp_ruler_unrealize;

#if GTK_CHECK_VERSION(3,0,0)

widget_class->get_preferred_width = sp_ruler_get_preferred_width;

widget_class->get_preferred_height = sp_ruler_get_preferred_height;

#else

widget_class->size_request = sp_ruler_size_request;

#endif

widget_class->size_allocate = sp_ruler_size_allocate;

widget_class->motion_notify_event = sp_ruler_motion_notify;

widget_class->expose_event = sp_ruler_expose;

klass->draw_ticks = sp_ruler_real_draw_ticks;

klass->draw_pos = sp_ruler_real_draw_pos;

g_object_class_override_property (gobject_class,

PROP_ORIENTATION,

"orientation");

g_object_class_install_property (gobject_class,

PROP_LOWER,

g_param_spec_double ("lower",

_("Lower"),

_("Lower limit of ruler"),

-G_MAXDOUBLE,

G_MAXDOUBLE,

0.0,

static_cast<GParamFlags>(GTK_PARAM_READWRITE)));

g_object_class_install_property (gobject_class,

PROP_UPPER,

g_param_spec_double ("upper",

_("Upper"),

_("Upper limit of ruler"),

-G_MAXDOUBLE,

G_MAXDOUBLE,

0.0,

static_cast<GParamFlags>(GTK_PARAM_READWRITE)));

g_object_class_install_property (gobject_class,

PROP_POSITION,

g_param_spec_double ("position",

_("Position"),

_("Position of mark on the ruler"),

-G_MAXDOUBLE,

G_MAXDOUBLE,

0.0,

static_cast<GParamFlags>(GTK_PARAM_READWRITE)));

g_object_class_install_property (gobject_class,

PROP_MAX_SIZE,

g_param_spec_double ("max-size",

_("Max Size"),

_("Maximum size of the ruler"),

-G_MAXDOUBLE,

G_MAXDOUBLE,

0.0,

static_cast<GParamFlags>(GTK_PARAM_READWRITE)));

/**

g_object_class_install_property (gobject_class,

PROP_METRIC,

g_param_spec_uint("metric",

_("Metric"),

_("The metric used for the ruler"),

0, 8,

SP_PX,

static_cast<GParamFlags>(GTK_PARAM_READWRITE)));

g_type_class_add_private (gobject_class, sizeof (SPRulerPrivate));

}

static void

sp_ruler_init (SPRuler *ruler)

{

ruler->priv = G_TYPE_INSTANCE_GET_PRIVATE(ruler,

SP_TYPE_RULER,

SPRulerPrivate);

SPRulerPrivate *priv = ruler->priv;

priv->orientation = GTK_ORIENTATION_HORIZONTAL;

priv->backing_store = NULL;

priv->xsrc = 0;

priv->ysrc = 0;

priv->slider_size = 0;

priv->lower = 0;

priv->upper = 0;

priv->position = 0;

priv->max_size = 0;

sp_ruler_set_metric(ruler, SP_PX);

}

sp_ruler_set_range (SPRuler *ruler,

gdouble lower,

gdouble upper,

gdouble position,

gdouble max_size)

{

g_return_if_fail (SP_IS_RULER (ruler));

SPRulerPrivate *priv = ruler->priv;

g_object_freeze_notify (G_OBJECT (ruler));

if (priv->lower != lower)

{

priv->lower = lower;

g_object_notify (G_OBJECT (ruler), "lower");

}

if (priv->upper != upper)

{

priv->upper = upper;

g_object_notify (G_OBJECT (ruler), "upper");

}

if (priv->position != position)

{

priv->position = position;

g_object_notify (G_OBJECT (ruler), "position");

}

if (priv->max_size != max_size)

{

priv->max_size = max_size;

g_object_notify (G_OBJECT (ruler), "max-size");

}

g_object_thaw_notify (G_OBJECT (ruler));

if (gtk_widget_is_drawable (GTK_WIDGET (ruler)))

gtk_widget_queue_draw (GTK_WIDGET (ruler));

}

sp_ruler_get_range (SPRuler *ruler,

gdouble *lower,

gdouble *upper,

gdouble *position,

gdouble *max_size)

{

g_return_if_fail (SP_IS_RULER (ruler));

SPRulerPrivate *priv = ruler->priv;

if (lower)

*lower = priv->lower;

if (upper)

*upper = priv->upper;

if (position)

*position = priv->position;

if (max_size)

*max_size = priv->max_size;

}

static void

sp_ruler_set_property (GObject *object,

guint prop_id,

const GValue *value,

GParamSpec *pspec)

{

SPRuler *ruler = SP_RULER (object);

SPRulerPrivate *priv = ruler->priv;

switch (prop_id)

{

case PROP_ORIENTATION:

priv->orientation = static_cast<GtkOrientation>(g_value_get_enum (value));

gtk_widget_queue_resize (GTK_WIDGET (ruler));

break;

case PROP_LOWER:

sp_ruler_set_range (ruler, g_value_get_double (value), priv->upper,

priv->position, priv->max_size);

break;

case PROP_UPPER:

sp_ruler_set_range (ruler, priv->lower, g_value_get_double (value),

priv->position, priv->max_size);

break;

case PROP_POSITION:

sp_ruler_set_range (ruler, priv->lower, priv->upper,

g_value_get_double (value), priv->max_size);

break;

case PROP_MAX_SIZE:

sp_ruler_set_range (ruler, priv->lower, priv->upper,

priv->position, g_value_get_double (value));

break;

case PROP_METRIC:

sp_ruler_set_metric(ruler, static_cast<SPMetric>(g_value_get_enum (value)));

break;

default:

G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

break;

}

}

static void

sp_ruler_get_property (GObject *object,

guint prop_id,

GValue *value,

GParamSpec *pspec)

{

SPRuler *ruler = SP_RULER (object);

SPRulerPrivate *priv = ruler->priv;

switch (prop_id)

{

case PROP_ORIENTATION:

g_value_set_enum (value, priv->orientation);

break;

case PROP_LOWER:

g_value_set_double (value, priv->lower);

break;

case PROP_UPPER:

g_value_set_double (value, priv->upper);

break;

case PROP_POSITION:

g_value_set_double (value, priv->position);

break;

case PROP_MAX_SIZE:

g_value_set_double (value, priv->max_size);

break;

case PROP_METRIC:

g_value_set_enum(value, sp_ruler_get_metric(ruler));

break;

default:

G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

break;

}

}

SPMetric sp_ruler_get_metric(SPRuler *ruler)

{

g_return_val_if_fail(SP_IS_RULER(ruler), static_cast<SPMetric>(0));

SPRulerPrivate *priv = ruler->priv;

for (size_t i = 0; i < G_N_ELEMENTS(sp_ruler_metrics); i++) {

if (priv->metric == &sp_ruler_metrics[i]) {

return static_cast<SPMetric>(i);

}

}

g_assert_not_reached ();

return static_cast<SPMetric>(0);

}

sp_ruler_draw_ticks (SPRuler *ruler)

{

g_return_if_fail (SP_IS_RULER (ruler));

if (SP_RULER_GET_CLASS (ruler)->draw_ticks)

SP_RULER_GET_CLASS (ruler)->draw_ticks (ruler);

}

sp_ruler_draw_pos (SPRuler *ruler)

{

g_return_if_fail (SP_IS_RULER (ruler));

if (SP_RULER_GET_CLASS (ruler)->draw_pos)

SP_RULER_GET_CLASS (ruler)->draw_pos (ruler);

}

static void

sp_ruler_realize (GtkWidget *widget)

{

GtkAllocation allocation;

SPRuler *ruler;

GdkWindow *window;

GdkWindowAttr attributes;

gint attributes_mask;

ruler = SP_RULER (widget);

gtk_widget_set_realized (widget, TRUE);

gtk_widget_get_allocation(widget, &allocation);

attributes.window_type = GDK_WINDOW_CHILD;

attributes.x = allocation.x;

attributes.y = allocation.y;

attributes.width = allocation.width;

attributes.height = allocation.height;

attributes.wclass = GDK_INPUT_OUTPUT;

attributes.visual = gtk_widget_get_visual (widget);

attributes.colormap = gtk_widget_get_colormap (widget);

attributes.event_mask = gtk_widget_get_events (widget);

attributes.event_mask |= (GDK_EXPOSURE_MASK |

GDK_POINTER_MOTION_MASK |

GDK_POINTER_MOTION_HINT_MASK);

attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;

window = gdk_window_new(gtk_widget_get_parent_window (widget),

&attributes, attributes_mask);

gtk_widget_set_window(widget, window);

gdk_window_set_user_data(window, ruler);

gtk_widget_style_attach(widget);

gtk_style_set_background(gtk_widget_get_style(widget),

window, GTK_STATE_ACTIVE);

sp_ruler_make_pixmap (ruler);

}

static void sp_ruler_unrealize(GtkWidget *widget)

{

SPRuler *ruler = SP_RULER (widget);

SPRulerPrivate *priv = ruler->priv;

if (priv->backing_store)

{

#if GTK_CHECK_VERSION(3,0,0)

cairo_surface_destroy(priv->backing_store);

#else

g_object_unref(priv->backing_store);

#endif

priv->backing_store = NULL;

}

GTK_WIDGET_CLASS (sp_ruler_parent_class)->unrealize (widget);

}

static void sp_ruler_size_request(GtkWidget *widget,

GtkRequisition *requisition)

{

SPRulerPrivate *priv = SP_RULER_GET_PRIVATE (widget);

GtkStyle *style = gtk_widget_get_style(widget);

if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)

{

requisition->width = style->xthickness * 2 + 1;

requisition->height = style->ythickness * 2 + RULER_WIDTH;

}

else

{

requisition->width = style->xthickness * 2 + RULER_WIDTH;

requisition->height = style->ythickness * 2 + 1;

}

}

#if GTK_CHECK_VERSION(3,0,0)

static void sp_ruler_get_preferred_width(GtkWidget *widget, gint *minimal_width, gint *natural_width)

{

GtkRequisition requisition;

sp_ruler_size_request(widget, &requisition);

*minimal_width = *natural_width = requisition.width;

}

static void sp_ruler_get_preferred_height(GtkWidget *widget, gint *minimal_height, gint *natural_height)

{

GtkRequisition requisition;

sp_ruler_size_request(widget, &requisition);

*minimal_height = *natural_height = requisition.height;

}

#endif

static void sp_ruler_size_allocate(GtkWidget *widget, GtkAllocation *allocation)

{

SPRuler *ruler = SP_RULER(widget);

GtkAllocation old_allocation;

gtk_widget_get_allocation(widget, &old_allocation);

gboolean resized = (old_allocation.width != allocation->width ||

old_allocation.height != allocation->height);

gtk_widget_set_allocation(widget, allocation);

if (gtk_widget_get_realized (widget))

{

gdk_window_move_resize(gtk_widget_get_window(widget),

allocation->x, allocation->y,

allocation->width, allocation->height);

if(resized)

sp_ruler_make_pixmap (ruler);

}

}

static gboolean

sp_ruler_expose (GtkWidget *widget,

GdkEventExpose *event)

{

if (gtk_widget_is_drawable (widget))

{

SPRuler *ruler = SP_RULER (widget);

SPRulerPrivate *priv = ruler->priv;

cairo_t *cr;

sp_ruler_draw_ticks (ruler);

cr = gdk_cairo_create(gtk_widget_get_window(widget));

#if GTK_CHECK_VERSION(3,0,0)

cairo_set_source_surface(cr, priv->backing_store, 0, 0);

#else

gdk_cairo_set_source_pixmap (cr, priv->backing_store, 0, 0);

#endif

gdk_cairo_region(cr, event->region);

cairo_fill (cr);

cairo_destroy (cr);

sp_ruler_draw_pos (ruler);

}

return FALSE;

}

static void sp_ruler_make_pixmap(SPRuler *ruler)

{

SPRulerPrivate *priv = ruler->priv;

GtkWidget *widget = GTK_WIDGET(ruler);

GtkAllocation allocation;

gtk_widget_get_allocation(widget, &allocation);

if (priv->backing_store)

#if GTK_CHECK_VERSION(3,0,0)

cairo_surface_destroy(priv->backing_store);

priv->backing_store = gdk_window_create_similar_surface(gtk_widget_get_window(widget),

CAIRO_CONTENT_COLOR,

allocation.width,

allocation.height);

#else

g_object_unref(priv->backing_store);

priv->backing_store = gdk_pixmap_new(gtk_widget_get_window(widget),

allocation.width,

allocation.height,

-1);

#endif

priv->xsrc = 0;

priv->ysrc = 0;

}

static void sp_ruler_real_draw_pos(SPRuler *ruler)

{

GtkAllocation allocation;

GtkWidget *widget = GTK_WIDGET (ruler);

SPRulerPrivate *priv = ruler->priv;

GtkStyle *style;

gint x, y;

gint width, height;

gint bs_width, bs_height;

gint xthickness;

gint ythickness;

gdouble increment;

if (gtk_widget_is_drawable (widget))

{

style = gtk_widget_get_style(widget);

gtk_widget_get_allocation(widget, &allocation);

xthickness = style->xthickness;

ythickness = style->ythickness;

width = allocation.width;

height = allocation.height;

if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)

{

height -= ythickness * 2;

bs_width = height / 2 + 2;

bs_width |= 1; /* make sure it's odd */

bs_height = bs_width / 2 + 1;

}

else

{

width -= xthickness * 2;

bs_height = width / 2 + 2;

bs_height |= 1; /* make sure it's odd */

bs_width = bs_height / 2 + 1;

}

if ((bs_width > 0) && (bs_height > 0))

{

GdkWindow *window = gtk_widget_get_window(widget);

cairo_t *cr = gdk_cairo_create(window);

/* If a backing store exists, restore the ruler */

if (priv->backing_store)

{

cairo_t *cr = gdk_cairo_create(window);

#if GTK_CHECK_VERSION(3,0,0)

cairo_set_source_surface(cr, priv->backing_store, 0, 0);

#else

gdk_cairo_set_source_pixmap(cr, priv->backing_store, 0, 0);

#endif

cairo_rectangle (cr, priv->xsrc, priv->ysrc, bs_width, bs_height);

cairo_fill (cr);

cairo_destroy (cr);

}

if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)

{

increment = (gdouble) width / (priv->upper - priv->lower);

x = ROUND ((priv->position - priv->lower) * increment) + (xthickness - bs_width) / 2 - 1;

y = (height + bs_height) / 2 + ythickness;

}

else

{

increment = (gdouble) height / (priv->upper - priv->lower);

x = (width + bs_width) / 2 + xthickness;

y = ROUND ((priv->position - priv->lower) * increment) + (ythickness - bs_height) / 2 - 1;

}

gdk_cairo_set_source_color(cr, &style->fg[gtk_widget_get_state(widget)]);

cairo_move_to (cr, x, y);

if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)

{

cairo_line_to (cr, x + bs_width / 2.0, y + bs_height);

cairo_line_to (cr, x + bs_width, y);

}

else

{

cairo_line_to (cr, x + bs_width, y + bs_height / 2.0);

cairo_line_to (cr, x, y + bs_height);

}

cairo_fill (cr);

cairo_destroy (cr);

priv->xsrc = x;

priv->ysrc = y;

}

}

}

#define UNUSED_PIXELS 2 // There appear to be two pixels that are not being used at each end of the ruler

GtkWidget* sp_ruler_new(GtkOrientation orientation)

{

return GTK_WIDGET(g_object_new(SP_TYPE_RULER,

"orientation", orientation,

NULL));

}

static gboolean sp_ruler_motion_notify(GtkWidget *widget,

GdkEventMotion *event)

{

GtkAllocation allocation;

SPRuler *ruler = SP_RULER(widget);

SPRulerPrivate *priv = ruler->priv;

gdk_event_request_motions(event);

gint x = event->x;

gint y = event->y;

gtk_widget_get_allocation(widget, &allocation);

if (priv->orientation == GTK_ORIENTATION_HORIZONTAL)

priv->position = priv->lower + (priv->upper - priv->lower) * (x + UNUSED_PIXELS) / (allocation.width + 2*UNUSED_PIXELS);

else

priv->position = priv->lower + (priv->upper - priv->lower) * (y + UNUSED_PIXELS) / (allocation.height + 2*UNUSED_PIXELS);

g_object_notify(G_OBJECT(ruler), "position");

/* Make sure the ruler has been allocated already */

if (priv->backing_store != NULL)

sp_ruler_draw_pos(ruler);

return FALSE;

}

static void sp_ruler_real_draw_ticks(SPRuler *ruler)

{

SPRulerPrivate *priv = ruler->priv;

gint width = 0;

gint height = 0;

gchar unit_str[32];

gchar digit_str[2] = { '\0', '\0' };

GtkOrientation orientation;

GtkAllocation allocation;

g_return_if_fail (ruler != NULL);

if (!gtk_widget_is_drawable (GTK_WIDGET (ruler)))

return;

g_object_get(G_OBJECT(ruler), "orientation", &orientation, NULL);

GtkWidget *widget = GTK_WIDGET (ruler);

GtkStyle *style = gtk_widget_get_style (widget);

PangoContext *pango_context = gtk_widget_get_pango_context (widget);

PangoLayout *pango_layout = pango_layout_new (pango_context);

PangoFontDescription *fs = pango_font_description_new ();

pango_font_description_set_size (fs, RULER_FONT_SIZE);

pango_layout_set_font_description (pango_layout, fs);

pango_font_description_free (fs);

gint digit_height = (int) floor (RULER_FONT_SIZE * RULER_FONT_VERTICAL_SPACING / PANGO_SCALE + 0.5);

gint xthickness = style->xthickness;

gint ythickness = style->ythickness;

gtk_widget_get_allocation (widget, &allocation);

if (orientation == GTK_ORIENTATION_HORIZONTAL) {

width = allocation.width; // in pixels; is apparently 2 pixels shorter than the canvas at each end

height = allocation.height;

} else {

width = allocation.height;

height = allocation.width;

}

#if GTK_CHECK_VERSION(3,0,0)

cairo_t *cr = cairo_create(priv->backing_store);

gtk_paint_box(style, cr,

GTK_STATE_NORMAL, GTK_SHADOW_NONE,

widget,

orientation == GTK_ORIENTATION_HORIZONTAL ? "hruler" : "vruler",

0, 0,

allocation.width, allocation.height);

#else

cairo_t *cr = gdk_cairo_create(priv->backing_store);

gtk_paint_box(style, priv->backing_store,

GTK_STATE_NORMAL, GTK_SHADOW_NONE, NULL, widget,

orientation == GTK_ORIENTATION_HORIZONTAL ? "hruler" : "vruler",

0, 0,

allocation.width, allocation.height);

#endif

cairo_set_line_width(cr, 1.0);

gdouble upper = priv->upper / priv->metric->pixels_per_unit; // upper and lower are expressed in ruler units

gdouble lower = priv->lower / priv->metric->pixels_per_unit;

/* "pixels_per_unit" should be "points_per_unit". This is the size of the unit

if ((upper - lower) == 0)

return;

double increment = (double) (width + 2*UNUSED_PIXELS) / (upper - lower); // screen pixels per ruler unit

/* determine the scale

gint scale = (int)(ceil(priv->max_size / priv->metric->pixels_per_unit));

sprintf (unit_str, "%d", scale);

gint text_dimension = strlen (unit_str) * digit_height + 1;

for (scale = 0; scale < MAXIMUM_SCALES; scale++)

if (priv->metric->ruler_scale[scale] * fabs(increment) > 2 * text_dimension)

break;

if (scale == MAXIMUM_SCALES)

scale = MAXIMUM_SCALES - 1;

/* drawing starts here */

gint length = 0;

for (gint i = MAXIMUM_SUBDIVIDE - 1; i >= 0; i--) {

double subd_incr = priv->metric->ruler_scale[scale] /

priv->metric->subdivide[i];

if (subd_incr * fabs(increment) <= MINIMUM_INCR)

continue;

/* Calculate the length of the tickmarks. Make sure that

gint ideal_length = height / (i + 1) - 1;

if (ideal_length > ++length)

length = ideal_length;

gdouble start = 0;

gdouble end = 0;

if (lower < upper) {

start = floor (lower / subd_incr) * subd_incr;

end = ceil (upper / subd_incr) * subd_incr;

} else {

start = floor (upper / subd_incr) * subd_incr;

end = ceil (lower / subd_incr) * subd_incr;

}

gint tick_index = 0;

gdouble cur = start; // location (in ruler units) of the first invisible tick at the left side of the canvas

while (cur <= end) {

// due to the typical values for cur, lower and increment, pos will often end up to

// be e.g. 641.50000000000; rounding behaviour is not defined in such a case (see round.h)

// and jitter will be apparent (upon redrawing some of the lines on the ruler might jump a

// by a pixel, and jump back on the next redraw). This is suppressed by adding 1e-9 (that's only one nanopixel ;-))

gint pos = int(Inkscape::round((cur - lower) * increment + 1e-12)) - UNUSED_PIXELS;

if (orientation == GTK_ORIENTATION_HORIZONTAL) {

cairo_move_to(cr, pos+0.5, height + ythickness);

cairo_line_to(cr, pos+0.5, height - length + ythickness);

} else {

cairo_move_to(cr, height + xthickness - length, pos+0.5);

cairo_line_to(cr, height + xthickness, pos+0.5);

}

/* draw label */

double label_spacing_px = fabs((increment*(double)priv->metric->ruler_scale[scale])/priv->metric->subdivide[i]);

if (i == 0 &&

(label_spacing_px > 6*digit_height || tick_index%2 == 0 || cur == 0) &&

(label_spacing_px > 3*digit_height || tick_index%4 == 0 || cur == 0))

{

if (fabs((int)cur) >= 2000 && (((int) cur)/1000)*1000 == ((int) cur))

sprintf (unit_str, "%dk", ((int) cur)/1000);

else

sprintf (unit_str, "%d", (int) cur);

if (orientation == GTK_ORIENTATION_HORIZONTAL) {

pango_layout_set_text (pango_layout, unit_str, -1);

cairo_move_to(cr, pos+2, 0);

pango_cairo_show_layout(cr, pango_layout);

} else {

for (gint j = 0; j < (int) strlen (unit_str); j++) {

digit_str[0] = unit_str[j];

pango_layout_set_text (pango_layout, digit_str, 1);

cairo_move_to(cr, xthickness + 1, pos + digit_height * (j) + 1);

pango_cairo_show_layout(cr, pango_layout);

}

}

}

/* Calculate cur from start rather than incrementing by subd_incr

++tick_index;

cur = start + tick_index * subd_incr;

cairo_stroke(cr);

}

}

cairo_destroy(cr);

}

void sp_ruler_set_metric(SPRuler *ruler, SPMetric metric)

{

g_return_if_fail(ruler != NULL);

g_return_if_fail(SP_IS_RULER (ruler));

g_return_if_fail((unsigned) metric < G_N_ELEMENTS(sp_ruler_metrics));

SPRulerPrivate *priv = ruler->priv;

if (metric == 0)

return;

priv->metric = const_cast<SPRulerMetric *>(&sp_ruler_metrics[metric]);

if (gtk_widget_is_drawable(GTK_WIDGET(ruler)))

gtk_widget_queue_draw(GTK_WIDGET(ruler));

g_object_notify(G_OBJECT(ruler), "metric");

}