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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/DRESSedAlarm184/LWXGL/llms.txt

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Rectangles, ellipses, and checkboxes are lightweight geometric UI elements. Rectangles and ellipses serve as structural and decorative shapes — borders, panels, and indicators. Checkboxes provide a familiar toggleable boolean control with an optional text label. All three accept separate foreground (border) and background (fill) color parameters; passing CLR_NONE (-1) for either omits that rendering layer entirely.

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CreateRect

void CreateRect(int id, int x, int y, int w, int h, int fg, int bg);
Creates a filled rectangle element. The foreground color is applied to the border (outline) and the background color fills the interior. Passing CLR_NONE for fg renders a filled rectangle with no visible border; passing CLR_NONE for bg renders only the border outline.
​
id
int
required
Unique element ID.
​
x
int
required
X coordinate of the top-left corner in pixels.
​
y
int
required
Y coordinate of the top-left corner in pixels.
​
w
int
required
Width of the rectangle in pixels.
​
h
int
required
Height of the rectangle in pixels.
​
fg
int
required
Border color — palette index (0–15), CLR_* constant, or CLR_NONE (-1) to omit the border.
​
bg
int
required
Fill color — palette index (0–15), CLR_* constant, or CLR_NONE (-1) to omit the fill (border-only mode).

​
CreateEllipse

void CreateEllipse(int id, int x, int y, int w, int h, int fg, int bg);
Creates an ellipse element inscribed within the bounding box defined by (x, y, w, h). As with CreateRect, fg paints the border and bg fills the interior; either may be CLR_NONE to suppress that layer.
​
id
int
required
Unique element ID.
​
x
int
required
X coordinate of the bounding box’s top-left corner in pixels.
​
y
int
required
Y coordinate of the bounding box’s top-left corner in pixels.
​
w
int
required
Width of the bounding box in pixels. The ellipse’s horizontal diameter equals w.
​
h
int
required
Height of the bounding box in pixels. The ellipse’s vertical diameter equals h. Pass equal w and h for a circle.
​
fg
int
required
Border color — palette index (0–15), CLR_* constant, or CLR_NONE to omit the border.
​
bg
int
required
Fill color — palette index (0–15), CLR_* constant, or CLR_NONE to omit the fill.

​
CreateCheckbox

void CreateCheckbox(int id, int x, int y, int size, int cb_col, int txt_col, const char* label);
Creates a checkbox element consisting of a square box and a text label to its right. Clicking anywhere within the element’s bounding box toggles the checked state. The element’s bounding box is size × size pixels; the label extends beyond it visually but hit-testing uses only the box region.
​
id
int
required
Unique element ID.
​
x
int
required
X coordinate of the checkbox square’s top-left corner in pixels.
​
y
int
required
Y coordinate of the checkbox square’s top-left corner in pixels.
​
size
int
required
Side length of the checkbox square in pixels. Both the element width and height are set to this value.
​
cb_col
int
required
Palette index for the checkmark glyph and the box border.
​
txt_col
int
required
Palette index for the label text rendered to the right of the box.
​
label
const char*
required
Null-terminated label string. The pointer is stored directly (not copied) and must remain valid for the element’s lifetime.

​
GetCheckbox

int GetCheckbox(int id);
Returns the current checked state of a checkbox element.
​
id
int
required
ID of an existing checkbox element.
Returns 1 if the checkbox is checked, 0 if unchecked.

​
Example

#include "libLWXGL.h"

#define ID_PANEL     0
#define ID_INDICATOR 1
#define ID_CHECKBOX  2

static void on_frame(int tick, float dt) {
    (void)tick; (void)dt;

    /* Change indicator color based on checkbox state */
    int checked = GetCheckbox(ID_CHECKBOX);
    DeleteElement(ID_INDICATOR);
    CreateEllipse(ID_INDICATOR, 160, 50, 40, 40,
                  CLR_NONE,
                  checked ? CLR_LGREEN : CLR_RED);
}

int main(void) {
    if (CreateWindow(300, 180, "Shape Demo", CLR_BLACK) != 0) return 1;

    /* Background panel */
    CreateRect(ID_PANEL, 10, 10, 280, 100, CLR_GRAY, CLR_LGRAY);

    /* Circular indicator, initially red */
    CreateEllipse(ID_INDICATOR, 160, 50, 40, 40, CLR_NONE, CLR_RED);

    /* Checkbox to toggle the indicator */
    CreateCheckbox(ID_CHECKBOX, 20, 50, 16, CLR_WHITE, CLR_WHITE, "Enable");

    MainWindowLoop(60, on_frame);
    TerminateWindow();
    return 0;
}
To use a rectangle as a divider or rule, set h to 1 (or w to 1 for a vertical rule) with bg as CLR_NONE and a foreground color for the border.

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