tut_ex14.c

Defining a table with widgets.

 
#include "unit_test.inc.h"
 
#ifndef _MSC_VER
// Silent gcc about unused "arg" in the callback and error functions
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif
 
static char *
cb_labels(void *tag, size_t r, size_t c) {
    static char buf[32];
 
    if (0==r && 0==c) {
        snprintf(buf, sizeof buf, "Device name:");
    } else if (0==r && 1==c) {
        snprintf(buf, sizeof buf, "Date:");
    } else if (1==r && 0==c) {
        snprintf(buf, sizeof buf, "Battery strength:");
    } else if (1==r && 1==c) {
        snprintf(buf, sizeof buf, "Signal:");
    } else {
        return NULL;
    }
    return buf;
}
 
 
static char *
cb_date(void *tag, size_t r, size_t c) {
    static char buf[64];
    if ( ! run_as_unit_test ) {
        time_t t = time(NULL);
        ctime_r(&t, buf);
        return buf;
    } else {
        return "Wed May 4 19:01:01 2022";
    }
}
 
static char *
cb_device_name(void *tag, size_t r, size_t c) {
    static char buf[32];
    snprintf(buf, sizeof buf, "IoT Device ABC123");
    return buf;
}
 
void
cb_draw_battery_widget(HPDF_Doc doc, HPDF_Page page, void *tag, size_t r,
                       size_t c, HPDF_REAL xpos, HPDF_REAL ypos,
                       HPDF_REAL width, HPDF_REAL height) {
    const HPDF_REAL segment_tot_width = width * 0.5;
    const HPDF_REAL segment_height = height / 3;
    const HPDF_REAL segment_xpos = xpos + 40;
    const HPDF_REAL segment_ypos = ypos + 4;
    const size_t num_segments = 10;
 
    const HPDF_RGBColor on_color = HPDF_COLOR_DARK_GREEN;
    const double val_percent = 0.4;
    const _Bool val_text_hide = FALSE;
 
    hpdftbl_widget_segment_hbar(
            doc, page, segment_xpos, segment_ypos, segment_tot_width,
            segment_height, num_segments, on_color, val_percent, val_text_hide);
}
 
void
cb_draw_signal_widget(HPDF_Doc doc, HPDF_Page page, void *tag, size_t r,
                      size_t c, HPDF_REAL xpos, HPDF_REAL ypos,
                      HPDF_REAL width, HPDF_REAL height) {
    const HPDF_REAL wwidth = 35;
    const HPDF_REAL wheight = 20;
    const HPDF_REAL wxpos = xpos + 70;
    const HPDF_REAL wypos = ypos + 4;
    const size_t num_segments = 5;
    const HPDF_RGBColor on_color = HPDF_COLOR_DARK_RED;
 
    // This should be the real data retrieved from a DB (for example)
    const size_t num_on_segments = 3;
 
    hpdftbl_widget_strength_meter(doc, page, wxpos, wypos, wwidth, wheight,
                                  num_segments, on_color, num_on_segments);
}
 
#ifndef _MSC_VER
#pragma GCC diagnostic pop
#endif
 
void
create_table_ex14(HPDF_Doc pdf_doc, HPDF_Page pdf_page) {
    const size_t num_rows = 2;
    const size_t num_cols = 2;
 
    char *table_title = "tut_ex14: 2x2 table widget callbacks";
    hpdftbl_t tbl = hpdftbl_create_title(num_rows, num_cols, table_title);
    hpdftbl_use_labels(tbl, TRUE);
    hpdftbl_use_labelgrid(tbl, TRUE);
 
    // Use one label callback for the entire table
    hpdftbl_set_label_cb(tbl, cb_labels);
 
    // Name in top left corner
    hpdftbl_set_cell_content_cb(tbl, 0, 0, cb_device_name);
 
    // Date in top right corner
    hpdftbl_set_cell_content_cb(tbl, 0, 1, cb_date);
 
    // Draw battery strength
    hpdftbl_set_cell_canvas_cb(tbl, 1, 0, cb_draw_battery_widget);
 
    // Draw signal strength
    hpdftbl_set_cell_canvas_cb(tbl, 1, 1, cb_draw_signal_widget);
 
    HPDF_REAL xpos = hpdftbl_cm2dpi(1);
    HPDF_REAL ypos = hpdftbl_cm2dpi(A4PAGE_HEIGHT_CM - 1);
    HPDF_REAL width = hpdftbl_cm2dpi(12);
    HPDF_REAL height = 0;  // Calculate height automatically
 
    // Stroke the table to the page
    hpdftbl_stroke(pdf_doc, pdf_page, tbl, xpos, ypos, width, height);
}
 
TUTEX_MAIN(create_table_ex14, FALSE)