danvics/oxipng
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Fix issues with 2-bit and 1-bit per pixel interlaced images [ci skip]

Browse source
This commit is contained in:
Joshua Holmer 2016-03-30 21:42:33 -04:00
parent 5740867be5
commit 7280ca80ce
1 changed files with 8 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
src/png.rs
View file

@ -157,27 +157,27 @@ impl<'a> Iterator for ScanLines<'a> {
let y_steps;
match self.pass {
Some((1, _)) => {
bits_per_line >>= 3;
bits_per_line = (bits_per_line as f32 / 8f32).ceil() as usize;
y_steps = 8;
}
Some((2, _)) => {
bits_per_line >>= 3;
bits_per_line = (bits_per_line as f32 / 8f32).ceil() as usize;
y_steps = 8;
}
Some((3, _)) => {
bits_per_line >>= 2;
bits_per_line = (bits_per_line as f32 / 4f32).ceil() as usize;
y_steps = 8;
}
Some((4, _)) => {
bits_per_line >>= 2;
bits_per_line = (bits_per_line as f32 / 4f32).ceil() as usize;
y_steps = 4;
}
Some((5, _)) => {
bits_per_line >>= 1;
bits_per_line = (bits_per_line as f32 / 2f32).ceil() as usize;
y_steps = 4;
}
Some((6, _)) => {
bits_per_line >>= 1;
bits_per_line = (bits_per_line as f32 / 2f32).ceil() as usize;
y_steps = 2;
}
Some((7, _)) => {
@ -201,11 +201,9 @@ impl<'a> Iterator for ScanLines<'a> {
bits_per_line -= gap;
}
}
// Round up without converting to float
let bytes_per_line = (bits_per_line + bits_per_line % 8) >> 3;
let bytes_per_line = (bits_per_line as f32 / 8f32).ceil() as usize;
self.start = self.end;
self.end = self.start + bytes_per_line + 1;
// TODO: Handle 4x4 pixel images
if let Some(pass) = self.pass.as_mut() {
if pass.1 + y_steps >= self.png.ihdr_data.height {
pass.0 += 1;
@ -228,8 +226,7 @@ impl<'a> Iterator for ScanLines<'a> {
let bits_per_line = self.png.ihdr_data.width as usize *
self.png.ihdr_data.bit_depth.as_u8() as usize *
self.png.channels_per_pixel() as usize;
// Round up without converting to float
let bytes_per_line = (bits_per_line + bits_per_line % 8) >> 3;
let bytes_per_line = (bits_per_line as f32 / 8f32).ceil() as usize;
self.start = self.end;
self.end = self.start + bytes_per_line + 1;
Some(ScanLine {