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add knob widget

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PROP 65 2024-08-19 00:48:39 +00:00 committed by GitHub
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src/nuklear_knob.c Normal file
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#include "nuklear.h"
#include "nuklear_internal.h"
/* ===============================================================
*
* KNOB
*
* ===============================================================*/
NK_LIB float
nk_knob_behavior(nk_flags *state, struct nk_input *in,
struct nk_rect bounds, float knob_min, float knob_max, float knob_value,
float knob_step, float knob_steps,
enum nk_heading zero_direction, float dead_zone_percent)
{
struct nk_vec2 origin;
float angle = 0.0f;
origin.x = bounds.x + (bounds.w / 2);
origin.y = bounds.y + (bounds.h / 2);
nk_widget_state_reset(state);
/* handle click and drag input */
if(in &&
in->mouse.buttons[NK_BUTTON_LEFT].down &&
nk_input_has_mouse_click_down_in_rect(in, NK_BUTTON_LEFT, bounds, nk_true)){
/* calculate angle from origin and rotate */
const float direction_rads[4] = {
NK_PI * 2.5f, /* 90 NK_UP */
NK_PI * 2.0f, /* 0 NK_RIGHT */
NK_PI * 1.5f, /* 270 NK_DOWN */
NK_PI, /* 180 NK_LEFT */
};
*state = NK_WIDGET_STATE_ACTIVE;
angle = NK_ATAN2(in->mouse.pos.y - origin.y, in->mouse.pos.x - origin.x) + direction_rads[zero_direction];
angle -= (angle > NK_PI * 2) ? NK_PI * 3 : NK_PI;
/* account for dead space applied when drawing */
angle *= 1.0f / (1.0f - dead_zone_percent);
angle = NK_CLAMP(-NK_PI, angle, NK_PI);
/* convert -pi -> pi range to 0.0 -> 1.0 */
angle = (angle + NK_PI) / (NK_PI * 2);
/* click to closest step */
knob_value = knob_min + ( (int)(angle * knob_steps + (knob_step / 2)) ) * knob_step;
knob_value = NK_CLAMP(knob_min, knob_value, knob_max);
}
/* knob widget state */
if (nk_input_is_mouse_hovering_rect(in, bounds)){
*state = NK_WIDGET_STATE_HOVERED;
if (in) {
/* handle scroll and arrow inputs */
if (in->mouse.scroll_delta.y > 0 ||
(in->keyboard.keys[NK_KEY_UP].down && in->keyboard.keys[NK_KEY_UP].clicked))
knob_value += knob_step;
if (in->mouse.scroll_delta.y < 0 ||
(in->keyboard.keys[NK_KEY_DOWN].down && in->keyboard.keys[NK_KEY_DOWN].clicked))
knob_value -= knob_step;
}
knob_value = NK_CLAMP(knob_min, knob_value, knob_max);
}
if (*state & NK_WIDGET_STATE_HOVER &&
!nk_input_is_mouse_prev_hovering_rect(in, bounds))
*state |= NK_WIDGET_STATE_ENTERED;
else if (nk_input_is_mouse_prev_hovering_rect(in, bounds))
*state |= NK_WIDGET_STATE_LEFT;
return knob_value;
}
NK_LIB void
nk_draw_knob(struct nk_command_buffer *out, nk_flags state,
const struct nk_style_knob *style, const struct nk_rect *bounds, float min, float value, float max,
enum nk_heading zero_direction, float dead_zone_percent)
{
const struct nk_style_item *background;
struct nk_color knob_color, cursor;
NK_UNUSED(min);
NK_UNUSED(max);
NK_UNUSED(value);
if (state & NK_WIDGET_STATE_ACTIVED) {
background = &style->active;
knob_color = style->knob_active;
cursor = style->cursor_active;
} else if (state & NK_WIDGET_STATE_HOVER) {
background = &style->hover;
knob_color = style->knob_hover;
cursor = style->cursor_hover;
} else {
background = &style->normal;
knob_color = style->knob_normal;
cursor = style->cursor_normal;
}
/* draw background */
switch(background->type) {
case NK_STYLE_ITEM_IMAGE:
nk_draw_image(out, *bounds, &background->data.image, nk_rgb_factor(nk_white, style->color_factor));
break;
case NK_STYLE_ITEM_NINE_SLICE:
nk_draw_nine_slice(out, *bounds, &background->data.slice, nk_rgb_factor(nk_white, style->color_factor));
break;
case NK_STYLE_ITEM_COLOR:
nk_fill_rect(out, *bounds, 0, nk_rgb_factor(background->data.color, style->color_factor));
nk_stroke_rect(out, *bounds, 0, style->border, nk_rgb_factor(style->border_color, style->color_factor));
break;
}
/* draw knob */
nk_fill_circle(out, *bounds, nk_rgb_factor(knob_color, style->color_factor));
if(style->knob_border > 0){
struct nk_rect border_bounds = *bounds;
border_bounds.x += style->knob_border / 2;
border_bounds.y += style->knob_border / 2;
border_bounds.w -= style->knob_border;
border_bounds.h -= style->knob_border;
nk_stroke_circle(out, border_bounds, style->knob_border, nk_rgb_factor(style->knob_border_color, style->color_factor));
}
{ /* calculate cursor line cords */
float half_circle_size = (bounds->w / 2);
float angle = (value - min) / (max - min);
float alive_zone = 1.0f - dead_zone_percent;
struct nk_vec2 cursor_start, cursor_end;
const float direction_rads[4] = {
NK_PI * 1.5f, /* 90 NK_UP */
0.0f, /* 0 NK_RIGHT */
NK_PI * 0.5f, /* 270 NK_DOWN */
NK_PI, /* 180 NK_LEFT */
};
/* calculate + apply dead zone */
angle = (angle * alive_zone) + (dead_zone_percent / 2);
/* percentage 0.0 -> 1.0 to radians, rads are 0.0 to (2*pi) NOT -pi to pi */
angle *= NK_PI * 2;
/* apply zero angle */
angle += direction_rads[zero_direction];
if(angle > NK_PI * 2)
angle -= NK_PI * 2;
cursor_start.x = bounds->x + half_circle_size + (angle > NK_PI);
cursor_start.y = bounds->y + half_circle_size + (angle < NK_PI_HALF || angle > (NK_PI * 1.5f));
cursor_end.x = cursor_start.x + (half_circle_size * NK_COS(angle));
cursor_end.y = cursor_start.y + (half_circle_size * NK_SIN(angle));
/* cut off half of the cursor */
cursor_start.x = (cursor_start.x + cursor_end.x) / 2;
cursor_start.y = (cursor_start.y + cursor_end.y) / 2;
/* draw cursor */
nk_stroke_line(out, cursor_start.x, cursor_start.y, cursor_end.x, cursor_end.y, 2, nk_rgb_factor(cursor, style->color_factor));
}
}
NK_LIB float
nk_do_knob(nk_flags *state,
struct nk_command_buffer *out, struct nk_rect bounds,
float min, float val, float max, float step,
enum nk_heading zero_direction, float dead_zone_percent,
const struct nk_style_knob *style, struct nk_input *in)
{
float knob_range;
float knob_min;
float knob_max;
float knob_value;
float knob_steps;
NK_ASSERT(style);
NK_ASSERT(out);
if (!out || !style)
return 0;
/* remove padding from knob bounds */
bounds.y = bounds.y + style->padding.y;
bounds.x = bounds.x + style->padding.x;
bounds.h = NK_MAX(bounds.h, 2*style->padding.y);
bounds.w = NK_MAX(bounds.w, 2*style->padding.x);
bounds.w -= 2 * style->padding.x;
bounds.h -= 2 * style->padding.y;
if(bounds.h < bounds.w){
bounds.x += (bounds.w - bounds.h) / 2;
bounds.w = bounds.h;
}
/* make sure the provided values are correct */
knob_max = NK_MAX(min, max);
knob_min = NK_MIN(min, max);
knob_value = NK_CLAMP(knob_min, val, knob_max);
knob_range = knob_max - knob_min;
knob_steps = knob_range / step;
knob_value = nk_knob_behavior(state, in, bounds, knob_min, knob_max, knob_value, step, knob_steps, zero_direction, dead_zone_percent);
/* draw knob */
if (style->draw_begin) style->draw_begin(out, style->userdata);
nk_draw_knob(out, *state, style, &bounds, knob_min, knob_value, knob_max, zero_direction, dead_zone_percent);
if (style->draw_end) style->draw_end(out, style->userdata);
return knob_value;
}
NK_API nk_bool
nk_knob_float(struct nk_context *ctx, float min_value, float *value, float max_value,
float value_step, enum nk_heading zero_direction, float dead_zone_degrees)
{
struct nk_window *win;
struct nk_panel *layout;
struct nk_input *in;
const struct nk_style *style;
int ret = 0;
float old_value;
struct nk_rect bounds;
enum nk_widget_layout_states state;
NK_ASSERT(ctx);
NK_ASSERT(ctx->current);
NK_ASSERT(ctx->current->layout);
NK_ASSERT(value);
NK_ASSERT(NK_BETWEEN(dead_zone_degrees, 0.0f, 360.0f));
if (!ctx || !ctx->current || !ctx->current->layout || !value)
return ret;
win = ctx->current;
style = &ctx->style;
layout = win->layout;
state = nk_widget(&bounds, ctx);
if (!state) return ret;
in = (state == NK_WIDGET_DISABLED || layout->flags & NK_WINDOW_ROM) ? 0 : &ctx->input;
old_value = *value;
*value = nk_do_knob(&ctx->last_widget_state, &win->buffer, bounds, min_value,
old_value, max_value, value_step, zero_direction, dead_zone_degrees / 360.0f, &style->knob, in);
return (old_value > *value || old_value < *value);
}
NK_API nk_bool
nk_knob_int(struct nk_context *ctx, int min, int *val, int max, int step,
enum nk_heading zero_direction, float dead_zone_degrees)
{
int ret;
float value = (float)*val;
ret = nk_knob_float(ctx, (float)min, &value, (float)max, (float)step, zero_direction, dead_zone_degrees);
*val = (int)value;
return ret;
}