Merge pull request #140 from lovasoa/improve_idct

HeroicKatora · web-flow · commit 785b8c38cacc · 2020-04-10T21:34:23.000+02:00
small idct code improvement
diff --git a/examples/decode.rs b/examples/decode.rs
@@ -1,7 +1,6 @@
 extern crate jpeg_decoder as jpeg;
 extern crate png;
 
-use png::HasParameters;
 use std::env;
 use std::fs::File;
 use std::io::{self, BufReader, Write};
diff --git a/src/idct.rs b/src/idct.rs
@@ -297,13 +297,7 @@ fn dequantize_and_idct_block_1x1(coefficients: &[i16], quantization_table: &[u16
 // take a -128..127 value and stbi__clamp it and convert to 0..255
 fn stbi_clamp(x: i32) -> u8
 {
-   // trick to use a single test to catch both cases
-   if x as u32 > 255 {
-      if x < 0 { return 0; }
-      if x > 255 { return 255; }
-   }
-
-   x as u8
+   x.max(0).min(255) as u8
 }
 
 fn stbi_f2f(x: f32) -> i32 {

Original file line number	Diff line number	Diff line change
`@@ -297,13 +297,7 @@ fn dequantize_and_idct_block_1x1(coefficients: &[i16], quantization_table: &[u16`
`297`	`297`	`// take a -128..127 value and stbi__clamp it and convert to 0..255`
`298`	`298`	`fn stbi_clamp(x: i32) -> u8`
`299`	`299`	`{`
`300`		`- // trick to use a single test to catch both cases`
`301`		`- if x as u32 > 255 {`
`302`		`- if x < 0 { return 0; }`
`303`		`- if x > 255 { return 255; }`
`304`		`- }`
`305`		`-`
`306`		`- x as u8`
	`300`	`+ x.max(0).min(255) as u8`
`307`	`301`	`}`
`308`	`302`
`309`	`303`	`fn stbi_f2f(x: f32) -> i32 {`