status-im/status-go

package images

const (
    UNKNOWN ImageType = 1 + iota

    // Raster image types
    JPEG
    PNG
    GIF
    WEBP
    ICO
)

const (
    MaxJpegQuality = 80
    MinJpegQuality = 50

    SmallDim = ResizeDimension(80)
    LargeDim = ResizeDimension(240)

    BannerDim = ResizeDimension(800)

    SmallDimName = "thumbnail"
    LargeDimName = "large"

    BannerIdentityName = "banner"
)

var (
    // ResizeDimensions list of all available image resize sizes
    ResizeDimensions = []ResizeDimension{SmallDim, LargeDim}

    // DimensionSizeLimit the size limits imposed on each resize dimension
    // Figures are based on the following sample data https://github.com/status-im/status-mobile/issues/11047#issuecomment-694970473
    DimensionSizeLimit = map[ResizeDimension]FileSizeLimits{
        SmallDim: {
            Ideal: 2560, // Base on the largest sample image at quality 60% (2,554 bytes ∴ 1024 * 2.5)
            Max:   5632, // Base on the largest sample image at quality 80% + 50% margin (3,683 bytes * 1.5 ≈ 5500 ∴ 1024 * 5.5)
        },
        LargeDim: {
            Ideal: 16384, // Base on the largest sample image at quality 60% (16,143 bytes ∴ 1024 * 16)
            Max:   38400, // Base on the largest sample image at quality 80% + 50% margin (24,290 bytes * 1.5 ≈ 37500 ∴ 1024 * 37.5)
        },
    }

    // ResizeDimensionToName maps a ResizeDimension to its assigned string name
    ResizeDimensionToName = map[ResizeDimension]string{
        SmallDim: SmallDimName,
        LargeDim: LargeDimName,
    }

    // NameToResizeDimension maps a string name to its assigned ResizeDimension
    NameToResizeDimension = map[string]ResizeDimension{
        SmallDimName: SmallDim,
        LargeDimName: LargeDim,
    }
)

type FileSizeLimits struct {
    Ideal int
    Max   int
}

type ImageType uint
type ResizeDimension uint

func GetBannerDimensionLimits() FileSizeLimits {
    return FileSizeLimits{
        Ideal: 307200, // We want to save space and traffic but keep to maximum compression
        Max:   460800, // Can't go bigger than 450 KB
    }
}