Description

The goal of this project is to create a GUI library which creates interfaces by compositing pre-made PNG image assets into a single flat image which takes up the whole window, as fast as possible.

Usage

Currently the project is under development, so the makefile includes flags for Address Sanitizer etc. which affects performance. If you are building this project, I recommend adjusting the makefile before you do.

The master header file is nagato.h, which includes compositing.h, key_constants.h, logo.h, png_image.h, scaling.h, and windowing.h. You can include nagato.h in order to use everything.

compositing

blend_with_background

Blends an image with a specified background color by modifying the image's pixel data in place. Assumes pixels are represented as four consecutive bytes (RGBA: Red, Green, Blue, Alpha) in a flat array. Sets the opacity to full for every pixel.

key_constants

See available key constants below

add an image with a keyboard and a map of each key constant here

logo

resources_nagato_png

An array of data representing a PNG image of the logo.

resources_nagato_png_len

The length of resources_nagato_png.

png_image

PNG_Image

A struct for storing PNG image data. It has width, height, bit depth, color type, and data attributes. Bytes per line can be calculated by multiplying the width by the number of channels (in the case of RGBA, width * 4).

png_load_from_memory

Loads a PNG image from a memory buffer into a custom PNG_Image structure. For example, this function can be used to load the logo. It takes a pointer to memory and the memory size, and returns a pointer to a PNG_Image struct.

png_load_from_file

Loads a PNG image from a file on disk into a custom PNG_Image structure. It takes a string filepath and returns a pointer to a PNG_Image struct.

CreatePNG_Image

Creates a PNG_Image struct with the given width, height, bit depth, and color type and returns a pointer to it. The image data is initialized as transparent black.

DestroyPNG_Image

Safely deallocates all memory used by the given PNG_Image struct.

scaling

nearest_neighbor_scale

Returns a new PNG_Image struct, which is scaled to the new width and height from the original image (given as a pointer to a PNG_Image). The PNG_Image is not deallocated or changed. The algorithm used is nearest neighbor, which is the fastest scaling algorithm, however typically results in a pixelated image or otherwise causes some clearly visible artifacting. Best used on images with very hard edges.

bilinear_interpolation_scale

Returns a new PNG_Image struct, which is scaled to the new width and height from the original image (given as a pointer to a PNG_Image). The PNG_Image is not deallocated or changed. The algorithm used is bilinear interpolation, which is better at handling gradual gradients than nearest neighbor, but may result in blurry images and is not ideal when sharp details are a priority.

windowing

shutdown

Raises a termination signal, which is handled to allow for the graceful shutdown of the GUI thread. This is functionally equivalent to closing the window.

update_image_from_memory

Given a pointer to a PNG_Image, the display is updated with the new image. The previous image is destroyed during this process using DestroyPNG_Image.

update_image_from_file

Given a filepath to a file on disk, the image is first loaded into memory using png_load_from_file and then the display is updated with the new image. The previous image is destroyed via DestroyPNG_Image

get_scaling_nn

Returns true if the scaling algorithm in use by the GUI is nearest neighbor scaling, false otherwise.

get_scaling_bli

Returns true if the scaling algorithm in use by the GUI is biliniear interpolation scaling, false otherwise.

set_scaling_nn

Sets the GUI to use nearest neighbor scaling. This is the fastest scaling algorithm, however typically results in a pixelated image or otherwise causes some clearly visible artifacting. Best used on images with very hard edges.

set_scaling_bli

Returns true if the scaling algorithm in use by the GUI is biliniear interpolation scaling, false otherwise. When no algorithm is set, the GUI will fall back on this algorithm. It is better at handling gradual gradients than nearest neighbor, but may result in blurry images and is not ideal when sharp details are a priority.

handle_key_event

Adds the given key handler to the given key. Whenever that key is pressed, the key handler will trigger immediately.

remove_key_handler

Removes the key handler for a particular key. After calling this function, nothing will happen when pressing that key.

get_mouse_position

Modifies the X and Y variable given to reflect the location of the mouse pointer, relative to the topleft corner of the window. The Y coordinate gets larger the further down in the window the mouse is, the X coordinate gets larger the further to the right in the window the mouse is. The topleft corner is (0, 0).

set_window_parameters

Sets the coordinates on the screen, the dimensions, and the border width of the window.

start_gui

Starts the GUI loop in the GUI thread. Blocks the current thread.

Planned Features and Improvements

• Mouse tracking
• Frame rate controls
• Image stack compositing/flattening
• Expanding multithreading capabilities
• Bicubic interpolation scaling
• Lanczos resampling scaling
• Box sampling
• Memory and CPU optimizations