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Merged
orsinium merged 1 commit into from
Feb 19, 2026
Merged

New image format (v2) #46

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2 changes: 1 addition & 1 deletion src/graphics_canvas.mbt
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ struct Canvas(FixedArray[Byte]) derive(Default)
///|
/// Create a new blank canvas.
pub fn Canvas::new(size : Size) -> Canvas {
Canvas(Image::new(size, bpp=4).0)
Canvas(Image::new(size).0)
}

///|
Expand Down
115 changes: 13 additions & 102 deletions src/graphics_image.mbt
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Original file line number Diff line number Diff line change
Expand Up @@ -6,50 +6,25 @@ struct Image(FixedArray[Byte]) derive(Default)

///|
/// Create a new blank image.
///
/// By default the image uses 4 bits-per-pixel (`bpp`).
/// The `bpp` must be either 1, 2, or 4.
pub fn Image::new(size : Size, bpp? : Byte = 4) -> Image {
guard bpp == 1 || bpp == 2 || bpp == 4 else { panic() }
let header_size = 5 + bpp.to_int() * 2
let body_size = size.w * size.h * bpp.to_int() / 8
pub fn Image::new(size : Size) -> Image {
let header_size = 4
let body_size = size.w * size.h / 2
let arr = FixedArray::make(header_size + body_size, Byte::default())
arr[0] = 0x21 // magic number
arr[1] = bpp
arr[2] = size.w.to_byte()
arr[3] = (size.w >> 8).to_byte()
arr[4] = 255 // transparency
for i in 0..<(2 * bpp.to_int()) {
arr[5 + i] = (((i * 2) << 4) | (i * 2 + 1)).to_byte()
}
arr[0] = 0x22 // magic number
arr[1] = size.w.to_byte()
arr[2] = (size.w >> 8).to_byte()
arr[3] = 0xff // no transparency
Image(arr)
}

///|
test "new image has correct bpp" {
inspect(Image::new(Size::new(20, 10), bpp=1).bpp(), content="1")
inspect(Image::new(Size::new(20, 10), bpp=2).bpp(), content="2")
inspect(Image::new(Size::new(20, 10), bpp=4).bpp(), content="4")
}

///|
test "new image has correct size" {
inspect(Image::new(Size::new(20, 10), bpp=1).size(), content="{w: 20, h: 10}")
inspect(Image::new(Size::new(20, 10), bpp=2).size(), content="{w: 20, h: 10}")
inspect(Image::new(Size::new(20, 10), bpp=4).size(), content="{w: 20, h: 10}")
inspect(Image::new(Size::new(20, 10)).size(), content="{w: 20, h: 10}")
}

///|
test "new image has correct pixel count" {
inspect(Image::new(Size::new(20, 10), bpp=1).pixels(), content="200")
inspect(Image::new(Size::new(20, 10), bpp=2).pixels(), content="200")
inspect(Image::new(Size::new(20, 10), bpp=4).pixels(), content="200")
}

///|
/// Convert the `Image` to a `File`.
pub fn Image::as_file(self : Image) -> File {
File(self.0)
inspect(Image::new(Size::new(20, 10)).pixels(), content="200")
}

///|
Expand All @@ -74,16 +49,10 @@ pub fn Image::sub(self : Image, point : Point, size : Size) -> SubImage {
}
}

///|
/// Bits per pixel. One of: 1, 2, or 4
pub fn Image::bpp(self : Image) -> Int {
self.0[1].to_int()
}

///|
/// The color used for transparency. If no transparency, returns `None`
pub fn Image::transparency(self : Image) -> Color {
match self.0[4] {
match self.0[3] {
_..<15 as c => Color::from_byte(c + 1)
_ => Color::None
}
Expand All @@ -103,14 +72,14 @@ pub fn Image::set_transparency(self : Image, color : Color) -> Unit {
///|
/// Returns the number of pixels the image has
pub fn Image::pixels(self : Image) -> Int {
let header_size = 5 + self.bpp() * 2
(self.0.length() - header_size) * 8 / self.bpp()
let header_size = 4
(self.0.length() - header_size) * 2
}

///|
/// Returns the width of the image (in pixels).
pub fn Image::width(self : Image) -> Int {
self.0[2].to_int() | (self.0[3].to_int() << 8)
self.0[1].to_int() | (self.0[2].to_int() << 8)
}

///|
Expand All @@ -130,61 +99,3 @@ pub fn Image::size(self : Image) -> Size {
_ as width => Size::new(width, self.pixels() / width)
}
}

///|
/// Get a color from the image color palette.
///
/// Palette index must be between 0-15 (includesive),
/// otherwise this function returns `Color::None`
pub fn Image::get_color(self : Image, index : Byte) -> Color {
if index > 15 {
return Color::None
}
let mut val = self.0[5 + index.to_int() / 2]
if index % 2 == 0 {
val = val >> 4
}
val = val & 0b1111
let transparentColor = self.0[4]
if val == transparentColor {
Color::None
} else {
Color::from_byte(val + 1)
}
}

///|
/// Set color in the image color palette.
///
/// Palette index must be between 0-15 (includesive),
/// otherwise this function is a no-op.
pub fn Image::set_color(self : Image, index : Byte, color : Color) -> Unit {
// ngl, this implementation looks kinda fishy.
// needs testing, 'cause I ain't believing this is working
if index > 15 || color is Color::None {
return
}
let byte_index = 5 + index.to_int() / 2
let mut val = self.0[byte_index]
let color_val = color.to_byte() - 1
if index % 2 == 0 {
val = (color_val << 4) | (val & 0b1111)
} else {
val = color_val | (val & 0b1111_0000)
}
self.0[byte_index] = val
}

///|
/// Replace one color in the image's color palette with another.
pub fn Image::replace_color(
self : Image,
old_color : Color,
new_color : Color,
) -> Unit {
for index = (0 : Byte); index < 16; index = index + 1 {
if self.get_color(index) == old_color {
self.set_color(index, new_color)
}
}
}
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