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Color table

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The choice of arbitrary RGB colors for use in graphic interfaces will not always be consistent with the desktop theme of the target platform. In Colors a series of "system" colors are defined and the possibility of creating alternative versions for light or dark themes. This demo shows this repertoire depending on the platform where the program runs. The source code is in folder /src/howto/colorview of the SDK distribution.

Capture a window with a color view.
Figure 1: Color table.
Listing 1: howto/colorview/colorview.c
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/* Color View */

#include "nappgui.h"

typedef struct _viewitem_t ViewItem;
typedef struct _app_t App;

struct _viewitem_t
{
    const char_t *name;
    color_t color;
};

struct _app_t
{
    Window *window;
    View *view;
    ArrSt(ViewItem) *items;
    uint32_t num_cols;
    Font *font;
};

static const real32_t i_ITEM_WIDTH = 64;
static const real32_t i_VER_MARGIN = 10;
static const real32_t i_HOR_MARGIN = 15;

/*---------------------------------------------------------------------------*/

static void i_add(ArrSt(ViewItem) *items, const char_t *name, const color_t color)
{
    ViewItem *item = arrst_new(items, ViewItem);
    item->name = name;
    item->color = color;
}

/*---------------------------------------------------------------------------*/

static ArrSt(ViewItem)* i_colors(void)
{
    ArrSt(ViewItem) *items = arrst_create(ViewItem);
    i_add(items, "Label", gui_label_color());
    i_add(items, "View", gui_view_color());
    i_add(items, "Line", gui_line_color());
    i_add(items, "Border", gui_border_color());
    i_add(items, "Link", gui_link_color());
    i_add(items, "Alt1", gui_alt_color(color_rgb(192, 255, 255), color_rgb(48, 112, 112)));
    i_add(items, "Alt2", gui_alt_color(color_rgb(255, 192, 255), color_rgb(128, 48, 112)));
    i_add(items, "Alt3", gui_alt_color(color_rgb(255, 255, 192), color_rgb(112, 112, 48)));
    i_add(items, "Black", kCOLOR_BLACK);
    i_add(items, "White", kCOLOR_WHITE);
    i_add(items, "Red", kCOLOR_RED);
    i_add(items, "Green", kCOLOR_GREEN);
    i_add(items, "Blue", kCOLOR_BLUE);
    i_add(items, "Yellow", kCOLOR_YELLOW);
    i_add(items, "Cyan", kCOLOR_CYAN);
    i_add(items, "Magenta", kCOLOR_MAGENTA);
    i_add(items, "Silver", color_rgb(192, 192, 192));
    i_add(items, "Gray", color_rgb(128, 128, 128));
    i_add(items, "Maroon", color_rgb(128, 0, 0));
    i_add(items, "Olive", color_rgb(128, 128, 0));
    i_add(items, "DGreen", color_rgb(0, 128, 0));
    i_add(items, "Teal", color_rgb(0, 128, 128));
    i_add(items, "Navy", color_rgb(0, 0, 128));
    i_add(items, "Purple", color_rgb(128, 0, 128));    
    return items;
}

/*---------------------------------------------------------------------------*/

static void i_draw(DCtx *ctx, real32_t x, real32_t y, real32_t width, real32_t height, const ViewItem *item)
{
    real32_t cx1 = x + width / 2;
    real32_t cx2 = x + (width - i_ITEM_WIDTH) / 2;
    real32_t cy = y + height - i_ITEM_WIDTH;
    draw_fill_color(ctx, item->color);
    draw_rect(ctx, ekFILL, cx2, cy, i_ITEM_WIDTH, i_ITEM_WIDTH);    
    draw_text_color(ctx, gui_label_color());
    draw_text(ctx, item->name, cx1, cy);
}

/*---------------------------------------------------------------------------*/

static void i_OnDraw(App *app, Event *e)
{
    const EvDraw *p = event_params(e, EvDraw);
    real32_t cwidth = (p->width - 2 * i_HOR_MARGIN) / app->num_cols;
    real32_t cheight = i_ITEM_WIDTH + font_height(app->font);

    draw_font(p->ctx, app->font);
    draw_text_align(p->ctx, ekCENTER, ekBOTTOM);
    
    arrst_foreach(item, app->items, ViewItem)
        uint32_t row = item_i / app->num_cols;
        uint32_t col = item_i % app->num_cols;
        real32_t x = i_HOR_MARGIN + col * cwidth;
        real32_t y = row * cheight + (row + 1) * i_VER_MARGIN;
        i_draw(p->ctx, x, y, cwidth, cheight, item);
    arrst_end();
}

/*---------------------------------------------------------------------------*/

static void i_OnSize(App *app, Event *e)
{
    const EvSize *p = event_params(e, EvSize);
    View *view = event_sender(e, View);
    real32_t minwidth = i_ITEM_WIDTH + 2 * i_HOR_MARGIN;
    real32_t cwidth = 0, cheight = 0;
    
    cwidth = p->width;
    
    if (cwidth < minwidth)
    {
        cwidth = minwidth;
        app->num_cols = 1;
    }
    else
    {
        uint32_t n, num_rows;
        app->num_cols = (uint32_t)((cwidth - i_HOR_MARGIN) / (i_ITEM_WIDTH + i_HOR_MARGIN));
        n = arrst_size(app->items, ViewItem);
        num_rows = (n / app->num_cols);
        if ((n % app->num_cols) > 0)
            num_rows += 1;

        cheight = num_rows * (i_ITEM_WIDTH + font_height(app->font) + i_VER_MARGIN) + i_VER_MARGIN;
        if (cheight < p->height)
            cheight = p->height;
    }
    
    view_content_size(view, s2df(cwidth, cheight), s2df(1, 1));
    view_update(view);
}

/*---------------------------------------------------------------------------*/

static Panel *i_panel(App *app)
{
    Panel *panel = panel_create();
    Layout *layout = layout_create(1, 1);
    View *view = view_scroll();
    view_size(view, s2df(300, 200));
    view_OnDraw(view, listener(app, i_OnDraw, App));
    view_OnSize(view, listener(app, i_OnSize, App));
    layout_view(layout, view, 0, 0);
    panel_layout(panel, layout);
    return panel;
}

/*---------------------------------------------------------------------------*/

static void i_OnClose(App *app, Event *e)
{
    osapp_finish();
    unref(app);
    unref(e);
}

/*---------------------------------------------------------------------------*/

static App *i_create(void)
{
    App *app = heap_new0(App);
    Panel *panel = i_panel(app);
    app->items = i_colors();
    app->font = font_system(font_regular_size(), 0);
    app->window = window_create(ekWNSRES, &panel);
    window_title(app->window, "Color View");
    window_origin(app->window, v2df(500, 200));
    window_size(app->window, s2df(500, 300));
    window_OnClose(app->window, listener(app, i_OnClose, App));
    window_show(app->window);
    return app;
}

/*---------------------------------------------------------------------------*/

static void i_destroy(App **app)
{
    arrst_destroy(&(*app)->items, NULL, ViewItem);
    window_destroy(&(*app)->window);
    font_destroy((&(*app)->font));
    heap_delete(app, App);
}

/*---------------------------------------------------------------------------*/

#include "osmain.h"
osmain(i_create, i_destroy, "", App)
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