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use core::{iter, slice};
use embedded_graphics::{
iterator::raw::RawDataSlice,
pixelcolor::raw::{LittleEndian, RawU1, RawU16, RawU24, RawU32, RawU4, RawU8},
prelude::*,
primitives::{rectangle, Rectangle},
};
use crate::{
header::{Bpp, CompressionMethod, RowOrder},
raw_bmp::RawBmp,
};
/// Iterator over raw pixel colors.
#[allow(missing_debug_implementations)]
pub struct RawColors<'a, R>
where
RawDataSlice<'a, R, LittleEndian>: IntoIterator<Item = R>,
{
rows: slice::ChunksExact<'a, u8>,
row_order: RowOrder,
current_row: iter::Take<<RawDataSlice<'a, R, LittleEndian> as IntoIterator>::IntoIter>,
width: usize,
}
impl<'a, R> RawColors<'a, R>
where
RawDataSlice<'a, R, LittleEndian>: IntoIterator<Item = R>,
{
pub(crate) fn new(raw_bmp: &'a RawBmp<'a>) -> Self {
let header = raw_bmp.header();
let width = header.image_size.width as usize;
Self {
rows: raw_bmp.image_data().chunks_exact(header.bytes_per_row()),
row_order: raw_bmp.header().row_order,
current_row: RawDataSlice::new(&[]).into_iter().take(0),
width,
}
}
}
impl<'a, R> Iterator for RawColors<'a, R>
where
RawDataSlice<'a, R, LittleEndian>: IntoIterator<Item = R>,
{
type Item = R;
fn next(&mut self) -> Option<Self::Item> {
self.current_row.next().or_else(|| {
let next_row = match self.row_order {
RowOrder::TopDown => self.rows.next(),
RowOrder::BottomUp => self.rows.next_back(),
}?;
self.current_row = RawDataSlice::new(next_row).into_iter().take(self.width);
self.current_row.next()
})
}
}
enum DynamicRawColors<'a> {
Bpp1(RawColors<'a, RawU1>),
Bpp4(RawColors<'a, RawU4>),
Bpp8(RawColors<'a, RawU8>),
Bpp16(RawColors<'a, RawU16>),
Bpp24(RawColors<'a, RawU24>),
Bpp32(RawColors<'a, RawU32>),
Bpp4Rle(Rle4Pixels<'a>),
Bpp8Rle(Rle8Pixels<'a>),
}
impl<'a> DynamicRawColors<'a> {
pub fn new(raw_bmp: &'a RawBmp<'a>) -> Self {
let header = raw_bmp.header();
match header.compression_method {
CompressionMethod::Rle4 => DynamicRawColors::Bpp4Rle(Rle4Pixels::new(raw_bmp)),
CompressionMethod::Rle8 => DynamicRawColors::Bpp8Rle(Rle8Pixels::new(raw_bmp)),
CompressionMethod::Rgb | CompressionMethod::Bitfields => match header.bpp {
Bpp::Bits1 => DynamicRawColors::Bpp1(RawColors::new(raw_bmp)),
Bpp::Bits4 => DynamicRawColors::Bpp4(RawColors::new(raw_bmp)),
Bpp::Bits8 => DynamicRawColors::Bpp8(RawColors::new(raw_bmp)),
Bpp::Bits16 => DynamicRawColors::Bpp16(RawColors::new(raw_bmp)),
Bpp::Bits24 => DynamicRawColors::Bpp24(RawColors::new(raw_bmp)),
Bpp::Bits32 => DynamicRawColors::Bpp32(RawColors::new(raw_bmp)),
},
}
}
}
/// The state for our RLE* decoder
#[derive(Debug)]
enum RleState {
/// Need to read two bytes
Starting,
/// Producing a sequence of identical values
Running {
remaining: u8,
value: u8,
is_odd: bool,
},
/// Producing a sequence of unique values
Absolute {
remaining: u8,
is_odd: bool,
has_padding: bool,
},
/// Ran out of pixels
EndOfBitmap,
}
/// Iterator over individual BMP RLE8 encoded pixels.
///
/// Each pixel is returned as a `u32` regardless of the bit depth of the source image.
#[derive(Debug)]
pub struct Rle8Pixels<'a> {
/// Our source data
data: &'a [u8],
/// Our state
rle_state: RleState,
/// The width of a line in pixels
width: u32,
/// The location of the next pixel
next_pixel: Point,
}
impl<'a> Rle8Pixels<'a> {
/// Create a new RLE pixel iterator.
pub(crate) fn new(raw_bmp: &RawBmp<'a>) -> Rle8Pixels<'a> {
let header = raw_bmp.header();
Rle8Pixels {
data: raw_bmp.image_data(),
rle_state: RleState::Starting,
width: header.image_size.width,
// RLE encoded bitmaps are upside down
next_pixel: Point::new(0, (header.image_size.height - 1) as i32),
}
}
/// Bump the cursor to the next position in the bitmap.
///
/// Note that RLE bitmaps are upside down.
fn move_position(&mut self) -> Point {
let old_position = self.next_pixel;
self.next_pixel.x += 1;
if self.next_pixel.x == self.width as i32 {
self.next_pixel.x = 0;
self.next_pixel.y = self.next_pixel.y.saturating_sub(1);
}
old_position
}
}
impl<'a> Iterator for Rle8Pixels<'a> {
type Item = RawPixel;
fn next(&mut self) -> Option<Self::Item> {
loop {
match self.rle_state {
RleState::EndOfBitmap => {
return None;
}
RleState::Absolute {
remaining,
is_odd,
has_padding,
} => {
if remaining == 0 {
self.rle_state = RleState::Starting;
} else {
self.rle_state = RleState::Absolute {
remaining: remaining.saturating_sub(1),
is_odd,
has_padding,
};
}
let value = *self.data.first()?;
if remaining == 0 && has_padding {
self.data = self.data.get(2..)?;
} else {
self.data = self.data.get(1..)?;
}
let this_pixel = self.move_position();
return Some(RawPixel::new(this_pixel, u32::from(value)));
}
RleState::Running {
remaining,
value,
is_odd,
} => {
if remaining == 0 {
self.rle_state = RleState::Starting;
} else {
self.rle_state = RleState::Running {
remaining: remaining.saturating_sub(1),
value,
is_odd,
};
}
let this_pixel = self.move_position();
return Some(RawPixel::new(this_pixel, u32::from(value)));
}
RleState::Starting => {
let length = *self.data.get(0)?;
let param = *self.data.get(1)?;
self.data = &self.data.get(2..)?;
match length {
0 => {
// The first byte of the pair can be set to zero to
// indicate an escape character that denotes the end of
// a line, the end of a bitmap, or a delta, depending on
// the value of the second byte. The interpretation of
// the escape depends on the value of the second byte of
// the pair, which can be one of the following values.
match param {
0 => {
// End of line
if self.next_pixel.x != 0 {
return None;
}
}
1 => {
// End of bitmap
self.rle_state = RleState::EndOfBitmap;
}
2 => {
// Delta encoding is unsupported.
return None;
}
_ => {
// Absolute mode
self.rle_state = RleState::Absolute {
remaining: param.saturating_sub(1),
is_odd: (param % 2) != 0,
// Odd lengths in RLE8 require 1 byte padding
has_padding: (param % 2) != 0,
};
}
}
}
_ => {
// An encoded run
self.rle_state = RleState::Running {
remaining: length.saturating_sub(1),
value: param,
is_odd: (length % 2) != 0,
};
}
}
}
}
}
}
}
/// Iterator over individual BMP RLE4 encoded pixels.
///
/// Each pixel is returned as a `u32` regardless of the bit depth of the source image.
#[derive(Debug)]
pub struct Rle4Pixels<'a> {
/// Our source data
data: &'a [u8],
/// Our state
rle_state: RleState,
/// The width of a line in pixels
width: u32,
/// The location of the next pixel
next_pixel: Point,
}
impl<'a> Rle4Pixels<'a> {
/// Create a new RLE pixel iterator.
pub(crate) fn new(raw_bmp: &RawBmp<'a>) -> Rle4Pixels<'a> {
let header = raw_bmp.header();
Rle4Pixels {
data: raw_bmp.image_data(),
rle_state: RleState::Starting,
width: header.image_size.width,
// RLE encoded bitmaps are upside down
next_pixel: Point::new(0, (header.image_size.height - 1) as i32),
}
}
/// Bump the cursor to the next position in the bitmap.
///
/// Note that RLE bitmaps are upside down.
fn move_position(&mut self) -> Point {
let old_position = self.next_pixel;
self.next_pixel.x += 1;
if self.next_pixel.x == self.width as i32 {
self.next_pixel.x = 0;
self.next_pixel.y = self.next_pixel.y.saturating_sub(1);
}
old_position
}
}
impl<'a> Iterator for Rle4Pixels<'a> {
type Item = RawPixel;
fn next(&mut self) -> Option<Self::Item> {
loop {
match self.rle_state {
RleState::EndOfBitmap => {
return None;
}
RleState::Absolute {
remaining,
is_odd,
has_padding,
} => {
// Here `remaining` is a count of nibbles, not bytes
// [00, 04, 45, 67] => 4 5 6 7
// ^ ^ ^ ^
// | | | +-- remaining is 0, is_odd is 0, we want [1]right
// | | +-- remaining is 1, is_odd is 0, we want [1]left
// | +-- remaining is 2, is_odd is 0, we want [0]right
// +-- remaining is 3, is_odd is 0, we want [0]left
// [00, 03, 45, 60] => 4 5 6
// ^ ^ ^
// | | +-- remaining is 0, is_odd is 1, we want [1]left
// | +-- remaining is 1, is_odd is 1, we want [0]right
// +-- remaining is 2, is_odd is 1, we want [0]left
let remaining_is_odd = (remaining % 2) != 0;
let want_left = remaining_is_odd != is_odd;
if remaining == 0 {
self.rle_state = RleState::Starting;
} else {
self.rle_state = RleState::Absolute {
remaining: remaining.saturating_sub(1),
is_odd,
has_padding,
};
}
let value = *self.data.first()?;
let nibble_value = if want_left { value >> 4 } else { value & 0x0F };
if !want_left || remaining == 0 {
self.data = self.data.get(1..)?;
}
if remaining == 0 && has_padding {
// remove the padding byte too
self.data = self.data.get(1..)?;
}
let this_pixel = self.move_position();
return Some(RawPixel::new(this_pixel, u32::from(nibble_value)));
}
RleState::Running {
remaining,
value,
is_odd,
} => {
// [03, 04] => 0 4 0
// ^ ^ ^
// | | +-- remaining is 0, is_odd is 1, we want left
// | +-- remaining is 1, is_odd is 1, we want right
// +-- remaining is 2, is_odd is 1, we want left
// [04, 04] => 0 4 0 4
// ^ ^ ^ ^
// | | | +-- remaining is 0, is_odd is 0, we want right
// | | +-- remaining is 1, is_odd is 0, we want left
// | +-- remaining is 2, is_odd is 0, we want right
// +-- remaining is 3, is_odd is 0, we want left
let remaining_is_odd = (remaining % 2) != 0;
let want_left = remaining_is_odd != is_odd;
let nibble_value = if want_left { value >> 4 } else { value & 0x0F };
if remaining == 0 {
self.rle_state = RleState::Starting;
} else {
self.rle_state = RleState::Running {
remaining: remaining.saturating_sub(1),
value,
is_odd,
};
}
let this_pixel = self.move_position();
return Some(RawPixel::new(this_pixel, u32::from(nibble_value)));
}
RleState::Starting => {
let length = *self.data.get(0)?;
let param = *self.data.get(1)?;
self.data = &self.data.get(2..)?;
match length {
0 => {
// The first byte of the pair can be set to zero to
// indicate an escape character that denotes the end of
// a line, the end of a bitmap, or a delta, depending on
// the value of the second byte. The interpretation of
// the escape depends on the value of the second byte of
// the pair, which can be one of the following values.
match param {
0 => {
// End of line
if self.next_pixel.x != 0 {
return None;
}
}
1 => {
// End of bitmap
self.rle_state = RleState::EndOfBitmap;
}
2 => {
// Delta encoding is unsupported.
return None;
}
_ => {
// Absolute mode
self.rle_state = RleState::Absolute {
remaining: param.saturating_sub(1),
is_odd: (param % 2) != 0,
// padding if the number of *bytes* is odd
has_padding: ((param >> 1) % 2) != 0,
};
}
}
}
_ => {
// An encoded run
self.rle_state = RleState::Running {
remaining: length.saturating_sub(1),
value: param,
is_odd: (length % 2) != 0,
};
}
}
}
}
}
}
}
/// Iterator over individual BMP pixels.
///
/// Each pixel is returned as a `u32` regardless of the bit depth of the source image.
#[allow(missing_debug_implementations)]
pub struct RawPixels<'a> {
colors: DynamicRawColors<'a>,
points: rectangle::Points,
}
impl<'a> RawPixels<'a> {
pub(crate) fn new(raw_bmp: &'a RawBmp<'a>) -> Self {
Self {
colors: DynamicRawColors::new(raw_bmp),
points: Rectangle::new(Point::zero(), raw_bmp.header().image_size).points(),
}
}
}
impl Iterator for RawPixels<'_> {
type Item = RawPixel;
fn next(&mut self) -> Option<Self::Item> {
let color = match &mut self.colors {
DynamicRawColors::Bpp1(colors) => colors.next().map(|r| u32::from(r.into_inner())),
DynamicRawColors::Bpp4(colors) => colors.next().map(|r| u32::from(r.into_inner())),
DynamicRawColors::Bpp8(colors) => colors.next().map(|r| u32::from(r.into_inner())),
DynamicRawColors::Bpp16(colors) => colors.next().map(|r| u32::from(r.into_inner())),
DynamicRawColors::Bpp24(colors) => colors.next().map(|r| r.into_inner()),
DynamicRawColors::Bpp32(colors) => colors.next().map(|r| r.into_inner()),
DynamicRawColors::Bpp4Rle(state) => {
return state.next();
}
DynamicRawColors::Bpp8Rle(state) => {
return state.next();
}
}?;
let position = self.points.next()?;
Some(RawPixel { position, color })
}
}
/// Pixel with raw pixel color stored as a `u32`.
#[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, Debug, Default)]
pub struct RawPixel {
/// The position relative to the top left corner of the image.
pub position: Point,
/// The raw pixel color.
pub color: u32,
}
impl RawPixel {
/// Creates a new raw pixel.
pub const fn new(position: Point, color: u32) -> Self {
Self { position, color }
}
}