mirror of
https://github.com/starovoid/rxing.git
synced 2026-07-26 12:22:34 +00:00
allignment pattern finder port
This commit is contained in:
Henry Schimke
319
src/qrcode/detector/alignment_pattern_finder.rs
Normal file
319
src/qrcode/detector/alignment_pattern_finder.rs
Normal file
@@ -0,0 +1,319 @@
|
||||
/*
|
||||
* Copyright 2007 ZXing authors
|
||||
*
|
||||
* Licensed under the Apache License, Version 2.0 (the "License");
|
||||
* you may not use this file except in compliance with the License.
|
||||
* You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing, software
|
||||
* distributed under the License is distributed on an "AS IS" BASIS,
|
||||
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
* See the License for the specific language governing permissions and
|
||||
* limitations under the License.
|
||||
*/
|
||||
|
||||
use crate::{common::BitMatrix, Exceptions, RXingResultPointCallback};
|
||||
|
||||
use super::AlignmentPattern;
|
||||
|
||||
/**
|
||||
* <p>This class attempts to find alignment patterns in a QR Code. Alignment patterns look like finder
|
||||
* patterns but are smaller and appear at regular intervals throughout the image.</p>
|
||||
*
|
||||
* <p>At the moment this only looks for the bottom-right alignment pattern.</p>
|
||||
*
|
||||
* <p>This is mostly a simplified copy of {@link FinderPatternFinder}. It is copied,
|
||||
* pasted and stripped down here for maximum performance but does unfortunately duplicate
|
||||
* some code.</p>
|
||||
*
|
||||
* <p>This class is thread-safe but not reentrant. Each thread must allocate its own object.</p>
|
||||
*
|
||||
* @author Sean Owen
|
||||
*/
|
||||
pub struct AlignmentPatternFinder {
|
||||
image: BitMatrix,
|
||||
possibleCenters: Vec<AlignmentPattern>,
|
||||
startX: u32,
|
||||
startY: u32,
|
||||
width: u32,
|
||||
height: u32,
|
||||
moduleSize: f32,
|
||||
crossCheckStateCount: [u32; 3],
|
||||
resultPointCallback: Option<RXingResultPointCallback>,
|
||||
}
|
||||
|
||||
impl AlignmentPatternFinder {
|
||||
/**
|
||||
* <p>Creates a finder that will look in a portion of the whole image.</p>
|
||||
*
|
||||
* @param image image to search
|
||||
* @param startX left column from which to start searching
|
||||
* @param startY top row from which to start searching
|
||||
* @param width width of region to search
|
||||
* @param height height of region to search
|
||||
* @param moduleSize estimated module size so far
|
||||
*/
|
||||
pub fn new(
|
||||
image: BitMatrix,
|
||||
startX: u32,
|
||||
startY: u32,
|
||||
width: u32,
|
||||
height: u32,
|
||||
moduleSize: f32,
|
||||
resultPointCallback: Option<RXingResultPointCallback>,
|
||||
) -> Self {
|
||||
Self {
|
||||
image,
|
||||
possibleCenters: Vec::with_capacity(5),
|
||||
startX,
|
||||
startY,
|
||||
width,
|
||||
height,
|
||||
moduleSize,
|
||||
crossCheckStateCount: [0u32; 3],
|
||||
resultPointCallback,
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>This method attempts to find the bottom-right alignment pattern in the image. It is a bit messy since
|
||||
* it's pretty performance-critical and so is written to be fast foremost.</p>
|
||||
*
|
||||
* @return {@link AlignmentPattern} if found
|
||||
* @throws NotFoundException if not found
|
||||
*/
|
||||
pub fn find(&mut self) -> Result<AlignmentPattern, Exceptions> {
|
||||
let startX = self.startX;
|
||||
let height = self.height;
|
||||
let maxJ = startX + self.width;
|
||||
let middleI = self.startY + (height / 2);
|
||||
// We are looking for black/white/black modules in 1:1:1 ratio;
|
||||
// this tracks the number of black/white/black modules seen so far
|
||||
let mut stateCount = vec![0u32; 3];
|
||||
for iGen in 0..height {
|
||||
// for (int iGen = 0; iGen < height; iGen++) {
|
||||
// Search from middle outwards
|
||||
let i = middleI
|
||||
+ (if (iGen & 0x01) == 0 {
|
||||
(iGen + 1) / 2
|
||||
} else {
|
||||
-((iGen as i32 + 1) / 2) as u32
|
||||
});
|
||||
stateCount[0] = 0;
|
||||
stateCount[1] = 0;
|
||||
stateCount[2] = 0;
|
||||
let mut j = startX;
|
||||
// Burn off leading white pixels before anything else; if we start in the middle of
|
||||
// a white run, it doesn't make sense to count its length, since we don't know if the
|
||||
// white run continued to the left of the start point
|
||||
while j < maxJ && !self.image.get(j, i) {
|
||||
j += 1;
|
||||
}
|
||||
let mut currentState = 0;
|
||||
while j < maxJ {
|
||||
if self.image.get(j, i) {
|
||||
// Black pixel
|
||||
if currentState == 1 {
|
||||
// Counting black pixels
|
||||
stateCount[1] += 1;
|
||||
} else {
|
||||
// Counting white pixels
|
||||
if currentState == 2 {
|
||||
// A winner?
|
||||
if self.foundPatternCross(&stateCount) {
|
||||
// Yes
|
||||
let confirmed = self.handlePossibleCenter(&stateCount, i, j);
|
||||
if confirmed.is_some() {
|
||||
return Ok(confirmed.unwrap());
|
||||
}
|
||||
}
|
||||
stateCount[0] = stateCount[2];
|
||||
stateCount[1] = 1;
|
||||
stateCount[2] = 0;
|
||||
currentState = 1;
|
||||
} else {
|
||||
currentState += 1;
|
||||
stateCount[currentState] += 1;
|
||||
}
|
||||
}
|
||||
} else {
|
||||
// White pixel
|
||||
if (currentState == 1) {
|
||||
// Counting black pixels
|
||||
currentState += 1;
|
||||
}
|
||||
stateCount[currentState] += 1;
|
||||
}
|
||||
j += 1;
|
||||
}
|
||||
if (self.foundPatternCross(&stateCount)) {
|
||||
let confirmed = self.handlePossibleCenter(&stateCount, i, maxJ);
|
||||
if (confirmed.is_some()) {
|
||||
return Ok(confirmed.unwrap());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Hmm, nothing we saw was observed and confirmed twice. If we had
|
||||
// any guess at all, return it.
|
||||
if (!self.possibleCenters.is_empty()) {
|
||||
return Ok(self.possibleCenters.get(0).unwrap().clone());
|
||||
}
|
||||
|
||||
Err(Exceptions::NotFoundException(
|
||||
"nothing to locate".to_owned(),
|
||||
))
|
||||
}
|
||||
|
||||
/**
|
||||
* Given a count of black/white/black pixels just seen and an end position,
|
||||
* figures the location of the center of this black/white/black run.
|
||||
*/
|
||||
fn centerFromEnd(stateCount: &[u32], end: u32) -> f32 {
|
||||
(end - stateCount[2]) as f32 - stateCount[1] as f32 / 2.0
|
||||
}
|
||||
|
||||
/**
|
||||
* @param stateCount count of black/white/black pixels just read
|
||||
* @return true iff the proportions of the counts is close enough to the 1/1/1 ratios
|
||||
* used by alignment patterns to be considered a match
|
||||
*/
|
||||
fn foundPatternCross(&self, stateCount: &[u32]) -> bool {
|
||||
let moduleSize = self.moduleSize;
|
||||
let maxVariance = moduleSize / 2.0;
|
||||
for i in 0..3 {
|
||||
// for (int i = 0; i < 3; i++) {
|
||||
if (moduleSize - stateCount[i] as f32).abs() >= maxVariance {
|
||||
return false;
|
||||
}
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>After a horizontal scan finds a potential alignment pattern, this method
|
||||
* "cross-checks" by scanning down vertically through the center of the possible
|
||||
* alignment pattern to see if the same proportion is detected.</p>
|
||||
*
|
||||
* @param startI row where an alignment pattern was detected
|
||||
* @param centerJ center of the section that appears to cross an alignment pattern
|
||||
* @param maxCount maximum reasonable number of modules that should be
|
||||
* observed in any reading state, based on the results of the horizontal scan
|
||||
* @return vertical center of alignment pattern, or {@link Float#NaN} if not found
|
||||
*/
|
||||
fn crossCheckVertical(
|
||||
&mut self,
|
||||
startI: u32,
|
||||
centerJ: u32,
|
||||
maxCount: u32,
|
||||
originalStateCountTotal: u32,
|
||||
) -> f32 {
|
||||
let image = &self.image;
|
||||
|
||||
let maxI = image.getHeight();
|
||||
// let mut stateCount = &self.crossCheckStateCount;
|
||||
self.crossCheckStateCount[0] = 0;
|
||||
self.crossCheckStateCount[1] = 0;
|
||||
self.crossCheckStateCount[2] = 0;
|
||||
|
||||
// Start counting up from center
|
||||
let mut i = startI;
|
||||
while i >= 0 && image.get(centerJ, i) && self.crossCheckStateCount[1] <= maxCount {
|
||||
self.crossCheckStateCount[1] += 1;
|
||||
i -= 1;
|
||||
}
|
||||
// If already too many modules in this state or ran off the edge:
|
||||
if i < 0 || self.crossCheckStateCount[1] > maxCount {
|
||||
return f32::NAN;
|
||||
}
|
||||
while i >= 0 && !image.get(centerJ, i) && self.crossCheckStateCount[0] <= maxCount {
|
||||
self.crossCheckStateCount[0] += 1;
|
||||
i -= 1;
|
||||
}
|
||||
if self.crossCheckStateCount[0] > maxCount {
|
||||
return f32::NAN;
|
||||
}
|
||||
|
||||
// Now also count down from center
|
||||
i = startI + 1;
|
||||
while i < maxI && image.get(centerJ, i) && self.crossCheckStateCount[1] <= maxCount {
|
||||
self.crossCheckStateCount[1] += 1;
|
||||
i += 1;
|
||||
}
|
||||
if i == maxI || self.crossCheckStateCount[1] > maxCount {
|
||||
return f32::NAN;
|
||||
}
|
||||
while i < maxI && !image.get(centerJ, i) && self.crossCheckStateCount[2] <= maxCount {
|
||||
self.crossCheckStateCount[2] += 1;
|
||||
i += 1;
|
||||
}
|
||||
if self.crossCheckStateCount[2] > maxCount {
|
||||
return f32::NAN;
|
||||
}
|
||||
|
||||
let stateCountTotal = self.crossCheckStateCount[0]
|
||||
+ self.crossCheckStateCount[1]
|
||||
+ self.crossCheckStateCount[2];
|
||||
if 5 * (stateCountTotal as i64 - originalStateCountTotal as i64).abs() as u32
|
||||
>= 2 * originalStateCountTotal
|
||||
{
|
||||
return f32::NAN;
|
||||
}
|
||||
|
||||
if self.foundPatternCross(&self.crossCheckStateCount) {
|
||||
Self::centerFromEnd(&self.crossCheckStateCount, i)
|
||||
} else {
|
||||
f32::NAN
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* <p>This is called when a horizontal scan finds a possible alignment pattern. It will
|
||||
* cross check with a vertical scan, and if successful, will see if this pattern had been
|
||||
* found on a previous horizontal scan. If so, we consider it confirmed and conclude we have
|
||||
* found the alignment pattern.</p>
|
||||
*
|
||||
* @param stateCount reading state module counts from horizontal scan
|
||||
* @param i row where alignment pattern may be found
|
||||
* @param j end of possible alignment pattern in row
|
||||
* @return {@link AlignmentPattern} if we have found the same pattern twice, or null if not
|
||||
*/
|
||||
fn handlePossibleCenter(
|
||||
&mut self,
|
||||
stateCount: &[u32],
|
||||
i: u32,
|
||||
j: u32,
|
||||
) -> Option<AlignmentPattern> {
|
||||
let stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2];
|
||||
let centerJ = Self::centerFromEnd(stateCount, j);
|
||||
let centerI = self.crossCheckVertical(
|
||||
i,
|
||||
centerJ.floor() as u32,
|
||||
2 * stateCount[1],
|
||||
stateCountTotal,
|
||||
);
|
||||
if !centerI.is_nan() {
|
||||
let estimatedModuleSize = (stateCount[0] + stateCount[1] + stateCount[2]) as f32 / 3.0;
|
||||
for center in &self.possibleCenters {
|
||||
// for (AlignmentPattern center : possibleCenters) {
|
||||
// Look for about the same center and module size:
|
||||
if center.aboutEquals(estimatedModuleSize, centerI, centerJ) {
|
||||
return Some(center.combineEstimate(centerI, centerJ, estimatedModuleSize));
|
||||
}
|
||||
}
|
||||
// Hadn't found this before; save it
|
||||
let point = AlignmentPattern::new(centerJ, centerI, estimatedModuleSize);
|
||||
if self.resultPointCallback.is_some() {
|
||||
self.resultPointCallback.as_ref().unwrap()(point.as_RXingResultPoint());
|
||||
}
|
||||
self.possibleCenters.push(point);
|
||||
// if self.resultPointCallback.is_some() {
|
||||
// self.resultPointCallback.as_ref().unwrap()(point.as_RXingResultPoint());
|
||||
// }
|
||||
}
|
||||
|
||||
None
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user