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#include <stdint.h>
#include <stdio.h>
#include <cairo.h>
#include <cairo-xcb.h>
#include <glib-object.h>
#include <pango/pango.h>
#include <pango/pangocairo.h>
#include <xcb/xcb.h>
#include <xcb/xcb_util.h>
enum CommandType
{
COMMAND_NOTHING,
COMMAND_DONE,
COMMAND_BLOCK,
COMMAND_SPAN,
};
union Command
{
int type;
struct {
int type;
int length;
const char * data;
} block;
struct {
int type;
int position;
int length;
} span;
};
struct State
{
int width;
int height;
xcb_connection_t * c;
xcb_screen_t * s;
xcb_visualtype_t * v;
xcb_window_t w;
cairo_t * ctx;
cairo_surface_t * surface;
};
int setup(struct State *);
void finalize(struct State *);
int handle(struct State *, xcb_generic_event_t *);
void draw_body(struct State *, union Command *);
xcb_visualtype_t * find_visual(xcb_screen_t *);
static const int MARGIN = 20;
static const char * const FONT = "Serif 16";
#define _BLOCK(_txt) {.block = {.type = COMMAND_BLOCK, .length = sizeof(_txt) - 1, .data = _txt}}
union Command body[] = {
{.span = {.type = COMMAND_SPAN, .position = 28, .length = 11}},
_BLOCK(
"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam auctor porta eros at tempus. Aliquam "
"elementum lectus id mi fermentum, non consectetur urna lobortis."
),
_BLOCK("Phasellus dignissim rhoncus magna at imperdiet."),
{.type = COMMAND_DONE},
};
#undef _BLOCK
int main(int argc, const char ** argv)
{
(void) argc;
(void) argv;
struct State state;
if (-1 == setup(&state))
{
dprintf(2, "Could not connect to X server\n"); // TODO: Helpful (specific) errors.
return 1;
}
for (;;)
{
xcb_generic_event_t * e = xcb_wait_for_event(state.c); // TODO: Change it to poll-like behaviour.
if (handle(&state, e))
break;
}
finalize(&state);
}
int setup(struct State * state)
{
static const int initial_width = 800;
static const int initial_height = 600;
state->c = xcb_connect(NULL, NULL);
if (xcb_connection_has_error(state->c))
return -1;
state->s = xcb_setup_roots_iterator(xcb_get_setup(state->c)).data;
state->w = xcb_generate_id(state->c);
state->v = find_visual(state->s);
const uint32_t mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
const uint32_t values[] = {
state->s->white_pixel,
XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS | XCB_EVENT_MASK_STRUCTURE_NOTIFY,
};
xcb_create_window(
state->c, XCB_COPY_FROM_PARENT, state->w, state->s->root, 0, 0, initial_width, initial_height, 0,
XCB_WINDOW_CLASS_INPUT_OUTPUT, state->s->root_visual, mask, values);
state->surface = cairo_xcb_surface_create(state->c, state->w, state->v, initial_width, initial_height);
state->ctx = cairo_create(state->surface);
xcb_map_window(state->c, state->w);
xcb_flush(state->c);
return 0;
}
void finalize(struct State * state)
{
cairo_destroy(state->ctx);
cairo_surface_destroy(state->surface);
xcb_disconnect(state->c);
}
int handle(struct State * state, xcb_generic_event_t * e)
{
switch (XCB_EVENT_RESPONSE_TYPE(e))
{
case XCB_KEY_PRESS:
free(e);
return 1;
case XCB_EXPOSE:
cairo_set_source_rgb(state->ctx, 1., 1., 1.);
cairo_paint(state->ctx);
draw_body(state, body); // TODO: Redraw outside of handler and don't use global body.
cairo_surface_flush(state->surface);
xcb_flush(state->c);
break;
case XCB_CONFIGURE_NOTIFY:
;
xcb_configure_notify_event_t * conf = (xcb_configure_notify_event_t *) e;
if (state->width != conf->width || state->height != conf->height)
{
cairo_xcb_surface_set_size(state->surface, conf->width, conf->height);
state->width = conf->width;
state->height = conf->height;
}
break;
default:
break;
}
free(e);
return 0;
}
xcb_visualtype_t * find_visual(xcb_screen_t * screen)
{
xcb_depth_iterator_t d = xcb_screen_allowed_depths_iterator(screen);
for (; d.rem; xcb_depth_next(&d))
{
xcb_visualtype_iterator_t v = xcb_depth_visuals_iterator(d.data);
for (; v.rem; xcb_visualtype_next(&v))
if (v.data->visual_id == screen->root_visual)
return v.data;
}
return NULL;
}
void draw_body(struct State * state, union Command * body)
{
PangoFontDescription * desc = pango_font_description_from_string(FONT);
cairo_set_source_rgb(state->ctx, 0., 0., 0.);
int y = MARGIN;
PangoAttrList * attrs = pango_attr_list_new(); // TODO-maybe: Don't recreate attributes lists each redraw?
for (union Command * command = body; COMMAND_DONE != command->type; ++command)
{
switch (command->type)
{
case COMMAND_SPAN:
;
PangoAttribute * attr = pango_attr_foreground_new(0x0000, 0x0000, 0xffff);
attr->start_index = command->span.position;
attr->end_index = command->span.position + command->span.length;
pango_attr_list_change(attrs, attr);
break;
case COMMAND_BLOCK:
cairo_move_to(state->ctx, MARGIN, y);
PangoLayout * layout = pango_cairo_create_layout(state->ctx);
pango_layout_set_attributes(layout, attrs);
pango_attr_list_unref(attrs);
attrs = pango_attr_list_new();
pango_layout_set_font_description(layout, desc);
pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
pango_layout_set_width(layout, (state->width - 2 * MARGIN) * PANGO_SCALE);
pango_layout_set_text(layout, command->block.data, command->block.length);
pango_cairo_update_layout(state->ctx, layout);
pango_cairo_show_layout(state->ctx, layout);
int height;
pango_layout_get_pixel_size(layout, NULL, &height);
y += height + MARGIN;
break;
case COMMAND_NOTHING:
default:
break;
}
}
pango_attr_list_unref(attrs);
pango_font_description_free(desc);
}
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