bogue 20231209 · OCaml Package

Low-level graphics and colors.

This module is internally used for low-level graphics and a thin layer over Tsdl.

The public API is mainly useful for Color management. There are also some helper functions for drawing into an Sdl_area.

Dependency graph

type canvas

Contains the hardware information for drawing (SDL renderer and window).

type texture = Tsdl.Sdl.texture

Initialization and shutdown

val video_init : unit -> unit

Manually init the SDL video system, and detect the scaling factor used by Bogue. This is useful only if you don't use Bogue's mainloop (for instance if you manually manage your windows and event loop).

val quit : unit -> unit

Cleanup and quit SDL.

Colors

type rgb = int * int * int

red, green and blue values are integers in the range 0..255

type color = int * int * int * int

r,g,b,a

type fill =

| Pattern of texture
| Solid of color

Predefined colors

val black : rgb

val grey : rgb

val pale_grey : rgb

val dark_grey : rgb

val white : rgb

val red : rgb

val blue : rgb

val green : rgb

val magenta : rgb

val cyan : rgb

val yellow : rgb

val sienna : rgb

val label_color : rgb

val none : color

none = (0,0,0,0) is completely transparent black.

Creating colors

val opaque : rgb -> color

val transp : rgb -> color

val lighter : color -> color

val darker : color -> color

val set_alpha : int -> rgb -> color

val random_color : unit -> color

val find_color : string -> rgb

Convert a string of the form "grey" or "#FE01BC" to a rgb code (r,g,b). Color names are taken from here.

val pale : rgb -> rgb

Using colors

val set_color : Tsdl.Sdl.renderer -> color -> unit

Equivalent to Sdl.set_render_draw_color.

val set_text_color : rgb -> unit

Overrides the Theme TEXT_COLOR variable.

Drawing functions

These functions can be used to draw onto an Sdl_area.t.

val to_pixels : (int * int) -> int * int

Convert BOGUE logical coordinates into hardware pixel coordinates. This takes into account both the Theme SCALE and the high-dpi scaling of some systems (mac OS retina, iOS).

val line : 
  ?thick:int ->
  Tsdl.Sdl.renderer ->
  color:color ->
  x0:int ->
  y0:int ->
  x1:int ->
  y1:int ->
  unit

val rectangle : 
  ?thick:int ->
  Tsdl.Sdl.renderer ->
  color:color ->
  w:int ->
  h:int ->
  x:int ->
  y:int ->
  unit

rectangle renderer ~color ~thick ~w ~h ~x ~y draws a rectangle with given line thickness. The coordinate of the top left corner is (x,y). The size (including the thick line) is (w,h).

val circle : 
  ?thick:int ->
  Tsdl.Sdl.renderer ->
  color:color ->
  radius:int ->
  x:int ->
  y:int ->
  unit

circle renderer ~width ~color ~radius ~x ~y draws a circle with given line thickness, centered at (x,y), with given radius.

Misc

type align =

| Min
| Center
| Max

val unscale_size : (int * int) -> int * int

Transform a size (W,H) in physical pixels into 'logical' pixels (w,h), which are used for layouts. This is done by dividing by the Theme SCALE variable.

val set_system_cursor : Tsdl.Sdl.System_cursor.t -> unit

Set the mouse cursor to be the standard system cursor. Internally, this first creates an SDL system cursor (or use a previously created one).

package bogue