Image and JPEG

JPEG methods allow you to decode, scale, cache, and render JPEG images directly onto displays. Images are provided as Base64 encoded JPEG data unless otherwise specified.

Methods

Method
clearJPEGCache() : ()
decodeAndScaleJPEG(base64JpegData : string, targetWidth : number, targetHeight : number) : table
decodeJPEG(base64JpegData : string) : table
getJPEGDimensions(base64JpegData : string) : table
getJPEGNetworkStats() : string
getRecommendedJPEGSettings(targetWidth : number, targetHeight : number) : table
loadJPEGFullscreen(displayId : DisplayID, base64JpegData : string) : ()
loadJPEGRegion(displayId : DisplayID, jpegBinaryData : string, x : number, y : number, w : number, h : number) : ()
loadJPEGRegionBytes(displayId : DisplayID, base64JpegData : string, x : number, y : number, w : number, h : number) : ()
preloadJPEGSequence(displayId : DisplayID, jpegSequence : table) : ()
restoreBackdrop(displayId : DisplayID, x : number, y : number, w : number, h : number) : ()
clearBackdrop(displayId : DisplayID) : ()

Generic Image Methods

These methods work with images in any supported format (PNG, GIF, JPEG, and others). The format is detected automatically.

Method
decodeAndScaleImage(base64ImageData : string, targetWidth : number, targetHeight : number) : table
decodeImage(base64ImageData : string) : table
detectImageFormat(base64ImageData : string) : string
getImageDimensions(base64ImageData : string) : table
loadImageFullscreen(displayId : DisplayID, base64ImageData : string) : ()
loadImageRegionBytes(displayId : DisplayID, base64ImageData : string, x : number, y : number, w : number, h : number) : ()
loadBlurredImage(displayId : DisplayID, image : string, options: [blur : number, brightness : number, saturation : number, bottomDim : number, x : number, y : number, w : number, h : number]) : ()
loadBlurredImageBytes(displayId : DisplayID, base64ImageData : string, options: [blur : number, brightness : number, saturation : number, bottomDim : number, x : number, y : number, w : number, h : number]) : ()
loadCoverImageRegion(displayId : DisplayID, image : string, x : number, y : number, w : number, h : number, scale : number, crop : number) : ()
loadCoverImageRegionBytes(displayId : DisplayID, base64ImageData : string, x : number, y : number, w : number, h : number, scale : number, crop : number) : ()

Usage

clearJPEGCache

Clears cached JPEG decoding data.

Useful when loading many images or when you want to free cached JPEG resources.

Example

gpu.clearJPEGCache()

---

decodeAndScaleJPEG

Decodes a Base64 JPEG image and scales it to the requested size.

Useful when you need image data before drawing.

Requires: base64JpegData : string, targetWidth : number, targetHeight : number

Returns: Image data table.

Example

local image = gpu.decodeAndScaleJPEG(
    base64JpegData,
    128,
    128
)

---

decodeJPEG

Decodes a Base64 JPEG image and returns its pixel data.

Requires: base64JpegData : string

Returns: Image data table.

Example

local image = gpu.decodeJPEG(base64JpegData)

---

getJPEGDimensions

Gets the dimensions of a JPEG without fully decoding or rendering it.

Requires: base64JpegData : string

Returns:

{
    width,
    height
}

Example

local dims = gpu.getJPEGDimensions(base64JpegData)

print(dims.width, dims.height)

---

getJPEGNetworkStats

Returns JPEG and network related statistics.

Returns: string

Example

print(gpu.getJPEGNetworkStats())

---

getRecommendedJPEGSettings

Returns recommended JPEG settings for a target resolution.

Useful for optimizing image transfer size and decoding performance.

Requires: targetWidth : number, targetHeight : number

Returns: table containing suggested settings.

Example

local settings = gpu.getRecommendedJPEGSettings(
    320,
    180
)

---

loadJPEGFullscreen

Decodes a JPEG image and fills the entire display with it.

Call updateDisplay afterwards to push the framebuffer.

Requires: DisplayID, base64JpegData : string

Example

gpu.loadJPEGFullscreen(displayId, base64JpegData)
gpu.updateDisplay(displayId)

---

loadJPEGRegion

Loads JPEG binary data into a specific region of a display.

Useful for updating only part of the framebuffer.

Requires: DisplayID, jpegBinaryData : string, x : number, y : number, w : number, h : number

Example

gpu.loadJPEGRegion(
    displayId,
    jpegBinaryData,
    0,
    0,
    100,
    100
)

---

loadJPEGRegionBytes

Loads a Base64 encoded JPEG into a specific display region.

This is the Base64 version of loadJPEGRegion.

Requires: DisplayID, base64JpegData : string, x : number, y : number, w : number, h : number

Example

gpu.loadJPEGRegionBytes(
    displayId,
    base64JpegData,
    50,
    50,
    128,
    128
)

---

preloadJPEGSequence

Preloads a sequence of JPEG images for later playback.

Useful for:

• slideshows
• animations
• video-like playback

Requires: DisplayID, jpegSequence : table

Example

gpu.preloadJPEGSequence(
    displayId,
    jpegSequence
)

---

restoreBackdrop

Restores the original backdrop in a rectangular region.

Requires: DisplayID, x : number, y : number, w : number, h : number

Example

gpu.restoreBackdrop(id, 100, 100, 80, 40)

gpu.fillRect(id, 100, 100, 80, 40, 255, 255, 255)
gpu.updateDisplay(id)
gpu.restoreBackdrop(id, 100, 100, 80, 40) -- Restores.
gpu.updateDisplay(id)

---

clearBackdrop

Discards the stored backdrop.

Requires: DisplayID

Example

gpu.clearBackdrop(id, 100, 100, 80, 40)

---

Usage

decodeAndScaleImage

Decodes a Base64 image (any supported format) and scales it to the requested size.

The image format is detected automatically.

Useful when you need image data before drawing.

Requires: base64ImageData : string, targetWidth : number, targetHeight : number

Returns: Image data table.

Example

local image = gpu.decodeAndScaleImage(
    base64ImageData,
    128,
    128
)

---

decodeImage

Decodes a Base64 image (any supported format) and returns its pixel data.

The image format is detected automatically.

Requires: base64ImageData : string

Returns: Image data table.

Example

local image = gpu.decodeImage(base64ImageData)

---

detectImageFormat

Detects the format of a Base64 image.

Requires: base64ImageData : string

Returns: Format name as a string (for example "png", "gif", or "jpeg").

Example

local format = gpu.detectImageFormat(base64ImageData)
print(format)

---

getImageDimensions

Gets the dimensions of an image without fully decoding or rendering it.

The image format is detected automatically.

Requires: base64ImageData : string

Returns:

{
    width,
    height
}

Example

local dims = gpu.getImageDimensions(base64ImageData)

print(dims.width, dims.height)

---

loadImageFullscreen

Decodes a Base64 image (any supported format) and fills the entire display with it.

Call updateDisplay afterwards to push the framebuffer.

Requires: DisplayID, base64ImageData : string

Example

gpu.loadImageFullscreen(displayId, base64ImageData)
gpu.updateDisplay(displayId)

---

loadImageRegionBytes

Loads a Base64 encoded image into a specific region of a display.

The image format is detected automatically.

Useful for updating only part of the framebuffer.

Requires: DisplayID, base64ImageData : string, x : number, y : number, w : number, h : number

Example

gpu.loadImageRegionBytes(
    displayId,
    base64ImageData,
    50,
    50,
    128,
    128
)

---

loadBlurredImage

Loads an image and renders it as a blurred backdrop.

Requires: DisplayID, image : string, options : table

Example

gpu.loadBlurredImage(
    displayId,
    image,
    {
      blur = 30,
      brightness = 0.5,
      saturation = 1,
      bottomDim = 0.3
    }
)

---

loadBlurredImageBytes

Loads a blurred image from encoded image bytes. Useful for things such as WebSocket, HTTP, Json, etc.

Requires: DisplayID, base64ImageData : string, options : table

Example

gpu.loadBlurredImage(
    displayId,
    image,
    {
      blur = 30,
      brightness = 0.5,
      saturation = 1,
      bottomDim = 0.3,
      x = 0, -- Optional
      y = 0,
      w = 384,
      h = 384,
    }
)

---

loadCoverImageRegion

Loads an image into a rectangular region.

Requires: DisplayID, image : string, x : number, y : number, w : number, h : number, scale : number, crop : number

Example

gpu.loadCoverImageRegion(
    displayId,
    image,
    20,
    20,
    160,
    160
)

---

loadCoverImageRegionBytes

Loads an image (base64 encoded) into a rectangular region. Useful for things such as WebSocket, HTTP, Json, etc.

Requires: DisplayID, base64ImageData : string, x : number, y : number, w : number, h : number, scale : number, crop : number

Example

gpu.loadCoverImageRegionBytes(
    displayId,
    imageb64,
    20,
    20,
    160,
    160
)