UXImage

UXImage is a width × height grid of packed 0xAARRGGBB pixels. It is the model behind the image well, canvas layers and thumbnails. A backend uploads and draws these images. The pixel arithmetic (compositing a sub-image in, clearing a region, cropping one out) lives here and can be tested without a backend. Colours pack and unpack through UXColor.

#use <UXKit>

Overview

UXImage* im = UXImage.make(64, 64);
im.fill(UXColor.rgba(255, 255, 255, 255));
im.fillRect(8, 8, 48, 48, UXColor.rgba(30, 90, 200, 255));
UXImage* thumb = im.subImage(0, 0, 32, 32);

Every mutation is clipped to the bounds. Writing off the edge writes nothing, and reading off the edge reads zero, so a blit near a corner needs no arithmetic from the caller.

Topics

Making · make · width / height Pixels · setPixel · pixelAt · setPixelRaw / pixelRaw · inBounds Regions · fill · fillRect · blit · subImage Packing · pack / unpack

make

static UXImage* make(i32 width, i32 height)

A new image, zero-filled (transparent black). Degenerate sizes become 1×1.

width / height

i32 width(void)
i32 height(void)

The dimensions.

setPixel

void setPixel(i32 x, i32 y, UXColor* c)

Writes one pixel; out of bounds writes nothing.

pixelAt

UXColor* pixelAt(i32 x, i32 y)

Reads one pixel as a colour; out of bounds reads transparent black.

setPixelRaw / pixelRaw

void setPixelRaw(i32 x, i32 y, u32 v)
u32  pixelRaw(i32 x, i32 y)

The packed-word forms, for tight loops.

inBounds

bool inBounds(i32 x, i32 y)

The clip test every mutation uses.

fill

void fill(UXColor* c)

Sets every pixel to one colour.

fillRect

void fillRect(i32 rx, i32 ry, i32 rw, i32 rh, UXColor* c)

A rectangle, clipped to bounds.

blit

void blit(UXImage* src, i32 dx, i32 dy)

Copies src in with its top-left at (dx, dy), clipped. It overwrites pixels with no alpha blending; compositing belongs to the graphics seam.

subImage

UXImage* subImage(i32 rx, i32 ry, i32 rw, i32 rh)

A new image cropped out of this one. Out-of-bounds source pixels come back as transparent black.

pack / unpack

static u32      pack(UXColor* c)
static UXColor* unpack(u32 v)

Conversion between the 0xAARRGGBB word and UXColor. It is public so pixel loops and tests can use both forms.