util/gfx/wtk_label.c

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#include <stdint.h>
#include <stdlib.h>
#include <assert.h>
#include <membag.h>
#include <string.h>
#include <gfx/wtk.h>

struct wtk_label {
        struct win_window       *container;
        char                    *caption;
        bool                    align_right;
};

struct win_window *wtk_label_as_child(struct wtk_label *label)
{
        assert(label);
        return label->container;
}

bool wtk_label_change(struct wtk_label *label, const char *caption)
{
        assert(label);
        assert(caption);

        uint8_t new_len = strlen(caption);
        uint8_t old_len = 0;

        if (caption) {
                old_len = strlen(label->caption);
        }

        /* Only free old memory if new length is longer than the
         * previous label.
         */
        if (new_len > old_len) {

                // Free old caption, if present.
                if (caption) {
                        membag_free(label->caption);
                }

                // Allocate memory for caption string, and copy text.
                label->caption = membag_alloc((new_len + 1) * sizeof(char));
                if (!label->caption) {
                        goto outofmem_caption;
                }
        }

        wtk_copy_string(label->caption, caption);

        // Redraw if visible.
        win_redraw(label->container);

        return true;

outofmem_caption:
        return false;
}

static bool wtk_label_handler(struct win_window *win,
                enum win_event_type type, void const *data)
{
        // Custom data for windows of a widget points back to the widget itself.
        struct wtk_label *label = (struct wtk_label *)win_get_custom_data(win);

        switch (type) {
        case WIN_EVENT_DRAW:
                {
                        // There should not be other windows in this widget.
                        assert(win == label->container);

                        /* For DRAW events, the data parameter points to the
                         * clipping region.
                         */
                        struct win_clip_region const *clip =
                                        (struct win_clip_region const *)data;
                        struct win_area const *area = win_get_area(win);

                        if (label->align_right == false) {
                                // Draw caption string.
                                gfx_draw_string(label->caption,
                                                clip->origin.x,
                                                clip->origin.y,
                                                &sysfont,
                                                WTK_STATICTEXT_CAPTION_COLOR,
                                                GFX_COLOR_TRANSPARENT);
                        } else {
                                // Get string size and draw the caption text right aligned.
                                gfx_coord_t width;
                                gfx_coord_t height;

                                gfx_get_string_bounding_box(label->caption,
                                                &sysfont, &width, &height);

                                gfx_draw_string(label->caption,
                                                clip->origin.x + area->size.x -
                                                width, clip->origin.y, &sysfont,
                                                WTK_STATICTEXT_CAPTION_COLOR,
                                                GFX_COLOR_TRANSPARENT);
                        }

                        /* Always accept DRAW events, as the return value is
                         * ignored anyway for that event type.
                         */
                        return true;
                }

        case WIN_EVENT_DESTROY:
                // There should not be other windows in this widget.
                assert(win == label->container);

                /* Memory allocated for windows will be automatically destroyed
                 * by the window system. We must destroy other allocations.
                 */
                membag_free(label->caption);
                membag_free(label);

                /* Always accept DESTROY events, as the return value is ignored
                 * anyway for that event type.
                 */
                return true;

        default:
                // Reject unknown event types.
                return false;
        }
}

void wtk_label_size_hint(struct win_point *size, const char *caption)
{
        assert(size);
        assert(caption);

        gfx_get_string_bounding_box(caption, &sysfont, &size->x, &size->y);
}

struct wtk_label *wtk_label_create(struct win_window *parent,
                struct win_area const *area,
                char const *caption, bool align_right)
{
        struct win_attributes   attr;
        struct wtk_label        *label;

        assert(area);
        assert(caption);
        assert(parent);

        // Allocate memory for label control data.
        label = membag_alloc(sizeof(struct wtk_label));
        if (!label) {
                goto outofmem_label;
        }

        label->align_right = align_right;

        // Allocate memory for caption string, and copy text.
        label->caption = membag_alloc((strlen(caption) + 1) * sizeof(char));
        if (!label->caption) {
                goto outofmem_caption;
        }

        wtk_copy_string(label->caption, caption);

        // Handling information.
        attr.event_handler = wtk_label_handler;
        attr.custom = label;

        // Prepare container frame.
        attr.area = *area;
        attr.background = NULL;
        attr.behavior = WIN_BEHAVIOR_REDRAW_PARENT;

        label->container = win_create(parent, &attr);
        if (!label->container) {
                goto outofmem_container;
        }

        return label;

outofmem_container:
        membag_free(label->caption);

outofmem_caption:
        membag_free(label);

outofmem_label:
        return NULL;
}

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