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font: refactor: extract cropping helper

This commit is contained in:
Wez Furlong 2023-08-16 11:04:21 -07:00
parent 560fa1f552
commit 847b1b7ab9
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GPG Key ID: 7A7F66A31EC9B387
3 changed files with 73 additions and 121 deletions

View File

@ -215,85 +215,26 @@ impl FreeTypeRasterizer {
&self,
pitch: usize,
ft_glyph: &FT_GlyphSlotRec_,
data: &[u8],
data: &'static [u8],
) -> RasterizedGlyph {
let width = ft_glyph.bitmap.width as usize;
let height = ft_glyph.bitmap.rows as usize;
let mut source_image = image::ImageBuffer::<image::Rgba<u8>, &[u8]>::from_raw(
width as u32,
height as u32,
data,
)
.expect("image data to be valid");
// emoji glyphs don't always fill the bitmap size, so we compute
// the non-transparent bounds here with this simplistic code.
// This can likely be improved!
// the non-transparent bounds
let mut first_line = None;
let mut first_col = None;
let mut last_col = None;
let mut last_line = None;
for y in 0..height {
let src_offset = y * pitch as usize;
for x in 0..width {
let alpha = data[src_offset + (x * 4) + 3];
if alpha != 0 {
if first_line.is_none() {
first_line = Some(y);
}
first_col = match first_col.take() {
Some(other) if x < other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
for y in (0..height).rev() {
let src_offset = y * pitch as usize;
for x in (0..width).rev() {
let alpha = data[src_offset + (x * 4) + 3];
if alpha != 0 {
if last_line.is_none() {
last_line = Some(y);
}
last_col = match last_col.take() {
Some(other) if x > other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
let first_line = first_line.unwrap_or(0);
let last_line = last_line.unwrap_or(0);
let first_col = first_col.unwrap_or(0);
let last_col = last_col.unwrap_or(0);
let dest_width = 1 + last_col - first_col;
let dest_height = 1 + last_line - first_line;
let size = (dest_width * dest_height * 4) as usize;
let mut rgba = vec![0u8; size];
for y in first_line..=last_line {
let src_offset = y * pitch as usize;
let dest_offset = (y - first_line) * dest_width * 4;
for x in first_col..=last_col {
let blue = data[src_offset + (x * 4)];
let green = data[src_offset + (x * 4) + 1];
let red = data[src_offset + (x * 4) + 2];
let alpha = data[src_offset + (x * 4) + 3];
let dest_x = x - first_col;
rgba[dest_offset + (dest_x * 4)] = red;
rgba[dest_offset + (dest_x * 4) + 1] = green;
rgba[dest_offset + (dest_x * 4) + 2] = blue;
rgba[dest_offset + (dest_x * 4) + 3] = alpha;
}
}
let cropped = crate::rasterizer::crop_to_non_transparent(&mut source_image).to_image();
let dest_width = cropped.width() as usize;
let dest_height = cropped.height() as usize;
RasterizedGlyph {
data: rgba,
data: cropped.into_vec(),
height: dest_height,
width: dest_width,
bearing_x: PixelLength::new(

View File

@ -486,55 +486,7 @@ impl<'a> PaintData<'a> {
}
// Crop to the non-transparent portions of the image
let mut first_line = None;
let mut first_col = None;
let mut last_col = None;
let mut last_line = None;
for (y, row) in decoded.rows().enumerate() {
for (x, pixel) in row.enumerate() {
let alpha = pixel[3];
if alpha != 0 {
if first_line.is_none() {
first_line = Some(y);
}
first_col = match first_col.take() {
Some(other) if x < other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
for (y, row) in decoded.rows().enumerate().rev() {
for (x, pixel) in row.enumerate().rev() {
let alpha = pixel[3];
if alpha != 0 {
if last_line.is_none() {
last_line = Some(y);
}
last_col = match last_col.take() {
Some(other) if x > other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
let first_col = first_col.unwrap_or(0) as u32;
let first_line = first_line.unwrap_or(0) as u32;
let last_col = last_col.unwrap_or(width as usize) as u32;
let last_line = last_line.unwrap_or(height as usize) as u32;
let cropped = image::imageops::crop(
&mut decoded,
first_col,
first_line,
last_col - first_col,
last_line - first_line,
)
.to_image();
let cropped = crate::rasterizer::crop_to_non_transparent(&mut decoded).to_image();
self.result.height = cropped.height() as usize;
self.result.width = cropped.width() as usize;

View File

@ -46,3 +46,62 @@ pub fn new_rasterizer(
)),
}
}
pub(crate) fn crop_to_non_transparent<'a, Container>(
image: &'a mut image::ImageBuffer<image::Rgba<u8>, Container>,
) -> image::SubImage<&'a mut image::ImageBuffer<image::Rgba<u8>, Container>>
where
Container: std::ops::Deref<Target = [u8]>,
{
let width = image.width();
let height = image.height();
let mut first_line = None;
let mut first_col = None;
let mut last_col = None;
let mut last_line = None;
for (y, row) in image.rows().enumerate() {
for (x, pixel) in row.enumerate() {
let alpha = pixel[3];
if alpha != 0 {
if first_line.is_none() {
first_line = Some(y);
}
first_col = match first_col.take() {
Some(other) if x < other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
for (y, row) in image.rows().enumerate().rev() {
for (x, pixel) in row.enumerate().rev() {
let alpha = pixel[3];
if alpha != 0 {
if last_line.is_none() {
last_line = Some(y);
}
last_col = match last_col.take() {
Some(other) if x > other => Some(x),
Some(other) => Some(other),
None => Some(x),
};
}
}
}
let first_col = first_col.unwrap_or(0) as u32;
let first_line = first_line.unwrap_or(0) as u32;
let last_col = last_col.unwrap_or(width as usize) as u32;
let last_line = last_line.unwrap_or(height as usize) as u32;
image::imageops::crop(
image,
first_col,
first_line,
last_col - first_col,
last_line - first_line,
)
}