zathura/adjustment.c
Abdo Roig-Maranges 030a8c65c1 add functions to compute page positions
The plan is to put in adjustment.c every piece of code that has to do
with document positioning, either computing it from data on the document
side, or talking to GTK.

We want to have at our disposal functions to compute sizes and positions
without having to ask for it to a GTK widget. The new functions are:

 - move page_calc_height_width to adjustment.c

 - add page_calc_position that rotates a position relative to a page
   according to the rotation settings.

 - add position_to_page_number that computes the number of a page
   sitting at a given position (given in document-relative coordinates)

 - add page_number_to_position that computes the position (in document
   relative coordinates) that will be placed at the center of the viewport.

 - add page_is_visible that checks whether the given page intersects the
   viewport.
2013-10-26 17:13:55 +02:00

195 lines
6.6 KiB
C

/* See LICENSE file for license and copyright information */
#include "adjustment.h"
#include "utils.h"
#include <math.h>
double
page_calc_height_width(zathura_document_t* document, double height, double width,
unsigned int* page_height, unsigned int* page_width, bool rotate)
{
g_return_val_if_fail(document != NULL && page_height != NULL && page_width != NULL, 0.0);
double scale = zathura_document_get_scale(document);
double real_scale;
if (rotate && zathura_document_get_rotation(document) % 180) {
*page_width = round(height * scale);
*page_height = round(width * scale);
real_scale = MAX(*page_width / height, *page_height / width);
} else {
*page_width = round(width * scale);
*page_height = round(height * scale);
real_scale = MAX(*page_width / width, *page_height / height);
}
return real_scale;
}
void
page_calc_position(zathura_document_t* document, double x, double y,
double *xn, double *yn) {
g_return_if_fail(document != NULL && xn != NULL && yn != NULL);
unsigned int rot = zathura_document_get_rotation(document);
if (rot == 90) {
*xn = 1 - y;
*yn = x;
}else if (rot == 180) {
*xn = 1 - x;
*yn = 1 - y;
} else if (rot == 270) {
*xn = y;
*yn = 1 - x;
} else {
*xn = x;
*yn = y;
}
}
unsigned int
position_to_page_number(zathura_document_t* document,
double pos_x, double pos_y){
g_return_val_if_fail(document != NULL, 0);
unsigned int doc_width, doc_height;
zathura_document_get_document_size(document, &doc_height, &doc_width);
unsigned int cell_width, cell_height;
zathura_document_get_cell_size(document, &cell_height, &cell_width);
unsigned int c0 = zathura_document_get_first_page_column(document);
unsigned int npag = zathura_document_get_number_of_pages(document);
unsigned int ncol = zathura_document_get_pages_per_row(document);
unsigned int nrow = (npag + c0 - 1 + ncol - 1) / ncol; /* number of rows */
unsigned int pad = zathura_document_get_page_padding(document);
unsigned int col = floor(pos_x * (double)doc_width / (double)(cell_width + pad));
unsigned int row = floor(pos_y * (double)doc_height / (double)(cell_height + pad));
return ncol * (row % nrow) + (col % ncol) - (c0 - 1);
}
void
page_number_to_position(zathura_document_t* document, unsigned int page_number,
double xalign, double yalign, double *pos_x, double *pos_y) {
g_return_if_fail(document != NULL);
unsigned int c0 = zathura_document_get_first_page_column(document);
unsigned int npag = zathura_document_get_number_of_pages(document);
unsigned int ncol = zathura_document_get_pages_per_row(document);
unsigned int nrow = (npag + c0 - 1 + ncol - 1) / ncol; /* number of rows */
/* row and column for page_number indexed from 0 */
unsigned int row = (page_number + c0 - 1) / ncol;
unsigned int col = (page_number + c0 - 1) % ncol;
/* sizes of page cell, viewport and document */
unsigned int cell_height = 0, cell_width = 0;
zathura_document_get_cell_size(document, &cell_height, &cell_width);
unsigned int view_height = 0, view_width = 0;
zathura_document_get_viewport_size(document, &view_height, &view_width);
unsigned int doc_height = 0, doc_width = 0;
zathura_document_get_document_size(document, &doc_height, &doc_width);
/* compute the shift to align to the viewport. If the page fits to viewport, just center it. */
double shift_x = 0.5, shift_y = 0.5;
if (cell_width > view_width) {
shift_x = 0.5 + (xalign - 0.5) * ((double)cell_width - (double)view_width) / (double)cell_width;
}
if (cell_height > view_height) {
shift_y = 0.5 + (yalign - 0.5) * ((double)cell_height - (double)view_height) / (double)cell_height;
}
/* compute the position */
*pos_x = ((double)col + shift_x) / (double)ncol;
*pos_y = ((double)row + shift_y) / (double)nrow;
}
bool
page_is_visible(zathura_document_t *document, unsigned int page_number) {
g_return_val_if_fail(document != NULL, false);
/* position at the center of the viewport */
double pos_x = zathura_document_get_position_x(document);
double pos_y = zathura_document_get_position_y(document);
/* get the center of page page_number */
double page_x, page_y;
page_number_to_position(document, page_number, 0.5, 0.5, &page_x, &page_y);
unsigned int cell_width, cell_height;
zathura_document_get_cell_size(document, &cell_height, &cell_width);
unsigned int doc_width, doc_height;
zathura_document_get_document_size(document, &doc_height, &doc_width);
unsigned int view_width, view_height;
zathura_document_get_viewport_size(document, &view_height, &view_width);
return ( fabs(pos_x - page_x) < 0.5 * (double)(view_width + cell_width) / (double)doc_width &&
fabs(pos_y - page_y) < 0.5 * (double)(view_height + cell_height) / (double)doc_height);
}
GtkAdjustment*
zathura_adjustment_clone(GtkAdjustment* adjustment)
{
gdouble value = gtk_adjustment_get_value(adjustment);
gdouble lower = gtk_adjustment_get_lower(adjustment);
gdouble upper = gtk_adjustment_get_upper(adjustment);
gdouble step_increment = gtk_adjustment_get_step_increment(adjustment);
gdouble page_increment = gtk_adjustment_get_page_increment(adjustment);
gdouble page_size = gtk_adjustment_get_page_size(adjustment);
return GTK_ADJUSTMENT(gtk_adjustment_new(value, lower, upper, step_increment,
page_increment, page_size));
}
void
zathura_adjustment_set_value(GtkAdjustment* adjustment, gdouble value)
{
gtk_adjustment_set_value(adjustment,
MAX(gtk_adjustment_get_lower(adjustment),
MIN(gtk_adjustment_get_upper(adjustment) -
gtk_adjustment_get_page_size(adjustment),
value)));
}
gdouble
zathura_adjustment_get_ratio(GtkAdjustment* adjustment)
{
gdouble lower = gtk_adjustment_get_lower(adjustment);
gdouble upper = gtk_adjustment_get_upper(adjustment);
gdouble page_size = gtk_adjustment_get_page_size(adjustment);
gdouble value = gtk_adjustment_get_value(adjustment);
return (value - lower + page_size / 2.0) / (upper - lower);
}
void
zathura_adjustment_set_value_from_ratio(GtkAdjustment* adjustment,
gdouble ratio)
{
if (ratio == 0.0) {
return;
}
gdouble lower = gtk_adjustment_get_lower(adjustment);
gdouble upper = gtk_adjustment_get_upper(adjustment);
gdouble page_size = gtk_adjustment_get_page_size(adjustment);
gdouble value = (upper - lower) * ratio + lower - page_size / 2.0;
zathura_adjustment_set_value(adjustment, value);
}