gp_widget_size_units.h

//SPDX-License-Identifier: LGPL-2.0-or-later
 
/*
 
   Copyright (c) 2014-2021 Cyril Hrubis <metan@ucw.cz>
 
 */
 
#ifndef GP_WIDGET_SIZE_UNITS_H
#define GP_WIDGET_SIZE_UNITS_H
 
#include <widgets/gp_widget_types.h>
#include <widgets/gp_widget_render.h>
 
/*
 * There are two fundamental constants that are used for widget size
 * computation. These are padding and text ascent. For example button widget
 * minimal height consists of ascent and two paddings one on the top and one
 * for the bottom.
 *
 * This structure describes a size as a sum of three different values these are
 * pixels, padding and ascent. The later two are relative to a render context
 * that defines the text ascent and padding.
 */
struct gp_widget_size {
        uint16_t px;
        uint8_t pad;
        uint8_t asc;
};
 
static inline unsigned int gp_widget_size_units_get(gp_widget_size *size,
                                                    const gp_widget_render_ctx *ctx)
{
        return size->px + ctx->padd * size->pad +
               gp_text_ascent(ctx->font) * size->asc;
}
 
int gp_widget_size_units_parse(const char *size, gp_widget_size *ret);
 
/*
 * Could be used to construct function parameters on the fly such as:
 *
 * w = gp_pixmap_create(GP_WIDGET_SIZE(100, 0, 0),
 *                      GP_WIDGET_SIZE(100, 0, 0),
 *                      callback, NULL);
 */
#define GP_WIDGET_SIZE(px_val, pad_val, asc_val) \
        ((gp_widget_size){.px = px_val, .pad = pad_val, .asc = asc_val})
 
/*
 * Special value used in widget constructors. When size is set to this value
 * the min size is set to a default for a given widget type.
 */
#define GP_WIDGET_SIZE_DEFAULT ((gp_widget_size){0xffff, 0xff, 0xff})
 
#define GP_WIDGET_SIZE_EQ(a, b) (((a).px == (b).px) && \
                                 ((a).pad == (b).pad) && \
                                 ((a).asc == (b).asc))
 
#endif /* GP_WIDGET_SIZE_UNITS_H */