BitmapUtil

BitmapUtil

Description

Util for bitmap operations

Functions

• writeBitmapToFile
• writeBitmapToFileFromIterator

writeBitmapToFile

Description

Saves a table of pixels into a portable anymap (pnm)

Definition

writeBitmapToFile(table pixels, integer width, integer height, string filepath, integer imageFormat)

Arguments

table	pixels	table of pixels, each pixel is a table
integer	width	image width in pixels
integer	height	image height in pixels
string	filepath	filepath for pnm
integer	imageFormat	image format, one of BitmapUtil.FORMAT

Return Values

integer	success

Code

function BitmapUtil.writeBitmapToFile(pixels, width, height, filepath, imageFormat)
    local maxBrightness = 255

    local pnmFormat = BitmapUtil.FORMAT_TO_PNM[imageFormat]

    if pnmFormat = = nil then
        Logging.error( "Invalid image format '%s'.Use one of BitmapUtil.FORMAT" , imageFormat)
        return false
    end

    filepath = string.format( "%s.%s" , filepath, pnmFormat.extension or "pnm" )
    local file = createFile(filepath, FileAccess.WRITE)
    if file = = 0 then
        Logging.error( "BitmapUtil.writeBitmapToFile():Unable to create file '%s'" , filepath)
        return false
    end

    -- Portable Anymap(PNM) Header
    fileWrite(file, pnmFormat.getHeader(width, height, maxBrightness))

    local pixelsToWrite = { }
    local concatFunc, clearFunc = table.concat , table.clear

    for pixelIndex = 1 , #pixels do
        pixelsToWrite[#pixelsToWrite + 1 ] = pnmFormat.getPixel(pixels[pixelIndex])
        if pixelIndex % 1025 = = 0 then
            fileWrite(file, concatFunc(pixelsToWrite))
            clearFunc(pixelsToWrite)
        end
    end

    if #pixelsToWrite > 0 then
        fileWrite(file, concatFunc(pixelsToWrite))
    end

    delete(file)

    Logging.info( "Wrote bitmap(width = %d, height = %d) to '%s'" , width, height, filepath)
    return true
end

writeBitmapToFileFromIterator

Description

Saves pixels into a portable anymap (pnm)

Definition

writeBitmapToFileFromIterator(function iterator, integer width, integer height, string filepath, integer imageFormat)

Arguments

function	iterator	iterator function returning the next pixel
integer	width	image width in pixels
integer	height	image height in pixels
string	filepath	filepath for pnm
integer	imageFormat	image format, one of BitmapUtil.FORMAT

Return Values

integer	success

Code

function BitmapUtil.writeBitmapToFileFromIterator(iterator, width, height, filepath, imageFormat)
    local pnmFormat = BitmapUtil.FORMAT_TO_PNM[imageFormat]

    if pnmFormat = = nil then
        Logging.error( "Invalid image format '%s'.Use one of BitmapUtil.FORMAT" , imageFormat)
        return false
    end

    filepath = string.format( "%s.%s" , filepath, pnmFormat.extension or "pnm" )
    local file = createFile(filepath, FileAccess.WRITE)
    if file = = 0 then
        Logging.error( "BitmapUtil.writeBitmapToFileFromIterator():Unable to create file '%s'" , filepath)
        return false
    end

    -- Portable Anymap(PNM) Header
    local maxBrightness = 255
    fileWrite(file, pnmFormat.getHeader(width, height, maxBrightness))

    local pixelsToWrite = { }
    local pixelIndex = 1
    local concatFunc, clearFunc = table.concat , table.clear

    for pixel in iterator() do
        pixelsToWrite[#pixelsToWrite + 1 ] = pnmFormat.getPixel(pixel)

        if pixelIndex % 1025 = = 0 then -- only write to file every 1024 pixels
            fileWrite(file, concatFunc(pixelsToWrite))
            clearFunc(pixelsToWrite)
        end

        pixelIndex = pixelIndex + 1
    end

    if #pixelsToWrite > 0 then
        fileWrite(file, concatFunc(pixelsToWrite))
    end

    delete(file)

    Logging.info( "Wrote bitmap(width = %d, height = %d) to '%s'" , width, height, filepath)
    return true
end