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Documentation Index

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The console widget provides a scrollable, terminal-style text pane that is useful for displaying real-time log output, debug information, or any stream of text lines. Text is appended with a printf-style interface, the view auto-scrolls to the bottom when new content arrives (provided the user has not scrolled up), and a scroll position overlay is shown on hover. The widget auto-sizes itself from the cols and rows parameters, eliminating manual pixel arithmetic.

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Dimensions

The pixel size of the console is computed automatically from the column and row counts: 
width  = cols * 9 + 17   /* 9 px per character + 8 px right margin for scrollbar */
height = rows * 15 + 10  /* 15 px per line + 10 px vertical padding              */

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Color Parameters

Both con_clr and txt_clr are packed color integers:
ParameterLow nibbleHigh nibble
con_clrConsole background fillConsole border / scrollbar thumb fill
txt_clrScrollbar fill (used for hover overlay background)Text color

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Character Rendering

  • Characters in the range 27–126 are rendered as-is.
  • Tab characters (\t) are expanded to 4 spaces before rendering.
  • Newline characters (\n) advance to the next line.
  • Any other byte (outside 27–126 and not \n or \t) is replaced with ?.

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Scroll Behavior

ActionEffect
Mouse wheel up (button 4)Scroll up 3 lines.
Mouse wheel down (button 5)Scroll down 3 lines.
Space key (while hovering)Jump to the bottom (last page).
ConsolePrint / new contentAuto-scroll to bottom if the view was already at the bottom before the print.
A status overlay (Viewing: start - end / total and Scroll: N%) is drawn over the console when the mouse pointer is inside the element.

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Functions

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CreateConsole

Creates a scrollable console widget. 
void CreateConsole(int id, int x, int y, int cols, int rows,
                   int con_clr, int txt_clr);
​
id
int
required
Unique integer identifier for this element.
​
x
int
required
Left edge of the console widget in pixels.
​
y
int
required
Top edge of the console widget in pixels.
​
cols
int
required
Number of character columns visible at once. The pixel width is computed as cols * 9 + 17. Lines longer than cols characters are wrapped automatically.
​
rows
int
required
Number of text rows visible at once. The pixel height is computed as rows * 15 + 10.
​
con_clr
int
required
Packed color for the console pane itself. Low nibble = background fill; high nibble = border and scrollbar thumb color.
​
txt_clr
int
required
Packed color for text. Low nibble = scrollbar/hover-overlay background; high nibble = text foreground color.

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ConsolePrint

Appends formatted text to the console’s internal buffer using printf-style format strings. If the view was already scrolled to the bottom before this call, it auto-scrolls to keep the latest content visible. 
void ConsolePrint(int id, const char* format, ...);
​
id
int
required
The identifier of the console element to print to.
​
format
const char*
required
A printf-compatible format string. The formatted output is appended verbatim to the internal std::string buffer. Include \n to start a new line.
​
...
variadic
Additional arguments matched to format specifiers in format, following the same rules as printf.
You do not need to append \n to every call — text wraps at cols characters automatically. However, using \n gives you explicit control over line breaks.

​
ConsoleClear

Clears all text from the console buffer and resets the scroll position to the top. 
void ConsoleClear(int id);
​
id
int
required
The identifier of the console element to clear.

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Code Example

#include "libLWXGL.h"
#include <stdio.h>

#define CON_ID 1
#define BTN_CLEAR 2

static int log_counter = 0;

static void on_clear(void) {
    ConsoleClear(CON_ID);
    log_counter = 0;
}

static void on_frame(int tick, float dt) {
    /* Log one line per second */
    static float acc = 0.0f;
    acc += dt;
    if (acc >= 1.0f) {
        acc -= 1.0f;
        ConsolePrint(CON_ID, "[%04d] tick=%d  dt=%.4f s\n",
                     log_counter++, tick, dt);
    }
}

int main(void) {
    CreateWindow(600, 400, "Log Viewer", CLR_BLACK, FLAG_NONE);

    /*
     * Console:
     *   con_clr: black fill (low), white border + scrollbar (high)
     *   txt_clr: gray overlay bg (low), light-green text (high)
     */
    int con_clr = CLR_BLACK | (CLR_WHITE  << 4);
    int txt_clr = CLR_GRAY  | (CLR_LGREEN << 4);

    /* 60 columns × 20 rows => 557 × 310 px */
    CreateConsole(CON_ID, 10, 10, 60, 20, con_clr, txt_clr);

    ConsolePrint(CON_ID, "=== Log started ===\n");

    /* Clear button below the console */
    int btn_u   = CLR_GRAY  | (CLR_WHITE << 4);
    int btn_hvr = CLR_LGRAY | (CLR_WHITE << 4);
    int btn_p   = CLR_BLACK | (CLR_LGRAY << 4);
    CreateButton(BTN_CLEAR, 10, 330, 100, 28, btn_u, btn_hvr, btn_p, "Clear", on_clear);

    MainWindowLoop(60, on_frame);
    TerminateWindow();
    return 0;
}

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