Keystroke to Screen Rendering Pipeline

What Happens Here

When you press a key, you physically close an electrical switch. The keyboard's microcontroller detects this change in the circuit. This is pure electrical and mechanical interaction—the foundation of all digital input.

What Happens Here

The firmware continuously scans the keyboard matrix to detect which key was pressed. It filters out electrical "bounce" (rapid on/off signals) and generates a scan code—a unique number for that key. This code is then packaged using the HID (Human Interface Device) protocol for transmission to the computer.

What Happens Here

The operating system kernel's device driver receives the signal via hardware interrupt. The interrupt handler processes this high-priority event, and the input subsystem converts the hardware-specific scan code into a standardized key code based on your keyboard layout (QWERTY, DVORAK, etc.).

What Happens Here

The window manager determines which application has focus and routes the keypress event to it. The Input Method Editor may compose multiple keypresses into a single character (important for languages like Chinese, Japanese, or when typing accented characters). The event is placed in the application's event queue.

What Happens Here

Your application (text editor, browser, etc.) receives the event and its event handler processes it. The character is inserted into the text buffer at the cursor position. The rendering engine then determines how to visually represent this character using the selected font, including kerning, anti-aliasing, and layout calculations.

What Happens Here

The graphics API sends rendering commands to the GPU, which processes them through shader programs to create the final pixels. These pixels are stored in the frame buffer, then sent by the display controller through HDMI/DisplayPort to your monitor, where liquid crystals or LEDs illuminate to show the character. Success!