mirror of
https://gitee.com/akwkevin/aistudio.-wpf.-diagram
synced 2026-04-08 18:26:35 +08:00
324 lines
12 KiB
C#
324 lines
12 KiB
C#
/*
|
|
* 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.
|
|
*/
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
|
|
using ZXing.Common;
|
|
|
|
namespace ZXing.QrCode.Internal
|
|
{
|
|
/// <summary> <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>
|
|
///
|
|
/// </summary>
|
|
/// <author> Sean Owen
|
|
/// </author>
|
|
/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
|
|
/// </author>
|
|
sealed class AlignmentPatternFinder
|
|
{
|
|
private readonly BitMatrix image;
|
|
private readonly IList<AlignmentPattern> possibleCenters;
|
|
private readonly int startX;
|
|
private readonly int startY;
|
|
private readonly int width;
|
|
private readonly int height;
|
|
private readonly float moduleSize;
|
|
private readonly int[] crossCheckStateCount;
|
|
private readonly ResultPointCallback resultPointCallback;
|
|
|
|
/// <summary> <p>Creates a finder that will look in a portion of the whole image.</p>
|
|
///
|
|
/// </summary>
|
|
/// <param name="image">image to search
|
|
/// </param>
|
|
/// <param name="startX">left column from which to start searching
|
|
/// </param>
|
|
/// <param name="startY">top row from which to start searching
|
|
/// </param>
|
|
/// <param name="width">width of region to search
|
|
/// </param>
|
|
/// <param name="height">height of region to search
|
|
/// </param>
|
|
/// <param name="moduleSize">estimated module size so far
|
|
/// </param>
|
|
internal AlignmentPatternFinder(BitMatrix image, int startX, int startY, int width, int height, float moduleSize, ResultPointCallback resultPointCallback)
|
|
{
|
|
this.image = image;
|
|
this.possibleCenters = new List<AlignmentPattern>(5);
|
|
this.startX = startX;
|
|
this.startY = startY;
|
|
this.width = width;
|
|
this.height = height;
|
|
this.moduleSize = moduleSize;
|
|
this.crossCheckStateCount = new int[3];
|
|
this.resultPointCallback = resultPointCallback;
|
|
}
|
|
|
|
/// <summary> <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>
|
|
///
|
|
/// </summary>
|
|
/// <returns> {@link AlignmentPattern} if found
|
|
/// </returns>
|
|
internal AlignmentPattern find()
|
|
{
|
|
int startX = this.startX;
|
|
int height = this.height;
|
|
int maxJ = startX + width;
|
|
int middleI = startY + (height >> 1);
|
|
// 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
|
|
int[] stateCount = new int[3];
|
|
for (int iGen = 0; iGen < height; iGen++)
|
|
{
|
|
// Search from middle outwards
|
|
int i = middleI + ((iGen & 0x01) == 0 ? ((iGen + 1) >> 1) : -((iGen + 1) >> 1));
|
|
stateCount[0] = 0;
|
|
stateCount[1] = 0;
|
|
stateCount[2] = 0;
|
|
int 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 && !image[j, i])
|
|
{
|
|
j++;
|
|
}
|
|
int currentState = 0;
|
|
while (j < maxJ)
|
|
{
|
|
if (image[j, i])
|
|
{
|
|
// Black pixel
|
|
if (currentState == 1)
|
|
{
|
|
// Counting black pixels
|
|
stateCount[currentState]++;
|
|
}
|
|
else
|
|
{
|
|
// Counting white pixels
|
|
if (currentState == 2)
|
|
{
|
|
// A winner?
|
|
if (foundPatternCross(stateCount))
|
|
{
|
|
// Yes
|
|
AlignmentPattern confirmed = handlePossibleCenter(stateCount, i, j);
|
|
if (confirmed != null)
|
|
{
|
|
return confirmed;
|
|
}
|
|
}
|
|
stateCount[0] = stateCount[2];
|
|
stateCount[1] = 1;
|
|
stateCount[2] = 0;
|
|
currentState = 1;
|
|
}
|
|
else
|
|
{
|
|
stateCount[++currentState]++;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// White pixel
|
|
if (currentState == 1)
|
|
{
|
|
// Counting black pixels
|
|
currentState++;
|
|
}
|
|
stateCount[currentState]++;
|
|
}
|
|
j++;
|
|
}
|
|
if (foundPatternCross(stateCount))
|
|
{
|
|
AlignmentPattern confirmed = handlePossibleCenter(stateCount, i, maxJ);
|
|
if (confirmed != null)
|
|
{
|
|
return confirmed;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Hmm, nothing we saw was observed and confirmed twice. If we had
|
|
// any guess at all, return it.
|
|
if (possibleCenters.Count != 0)
|
|
{
|
|
return possibleCenters[0];
|
|
}
|
|
|
|
return null;
|
|
}
|
|
|
|
/// <summary> 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.
|
|
/// </summary>
|
|
private static float? centerFromEnd(int[] stateCount, int end)
|
|
{
|
|
var result = (end - stateCount[2]) - stateCount[1] / 2.0f;
|
|
if (Single.IsNaN(result))
|
|
return null;
|
|
return result;
|
|
}
|
|
|
|
/// <param name="stateCount">count of black/white/black pixels just read
|
|
/// </param>
|
|
/// <returns> 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
|
|
/// </returns>
|
|
private bool foundPatternCross(int[] stateCount)
|
|
{
|
|
float maxVariance = moduleSize / 2.0f;
|
|
for (int i = 0; i < 3; i++)
|
|
{
|
|
if (Math.Abs(moduleSize - stateCount[i]) >= maxVariance)
|
|
{
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// <summary>
|
|
/// <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>
|
|
/// </summary>
|
|
/// <param name="startI">row where an alignment pattern was detected</param>
|
|
/// <param name="centerJ">center of the section that appears to cross an alignment pattern</param>
|
|
/// <param name="maxCount">maximum reasonable number of modules that should be
|
|
/// observed in any reading state, based on the results of the horizontal scan</param>
|
|
/// <param name="originalStateCountTotal">The original state count total.</param>
|
|
/// <returns>
|
|
/// vertical center of alignment pattern, or null if not found
|
|
/// </returns>
|
|
private float? crossCheckVertical(int startI, int centerJ, int maxCount, int originalStateCountTotal)
|
|
{
|
|
int maxI = image.Height;
|
|
int[] stateCount = crossCheckStateCount;
|
|
stateCount[0] = 0;
|
|
stateCount[1] = 0;
|
|
stateCount[2] = 0;
|
|
|
|
// Start counting up from center
|
|
int i = startI;
|
|
while (i >= 0 && image[centerJ, i] && stateCount[1] <= maxCount)
|
|
{
|
|
stateCount[1]++;
|
|
i--;
|
|
}
|
|
// If already too many modules in this state or ran off the edge:
|
|
if (i < 0 || stateCount[1] > maxCount)
|
|
{
|
|
return null;
|
|
}
|
|
while (i >= 0 && !image[centerJ, i] && stateCount[0] <= maxCount)
|
|
{
|
|
stateCount[0]++;
|
|
i--;
|
|
}
|
|
if (stateCount[0] > maxCount)
|
|
{
|
|
return null;
|
|
}
|
|
|
|
// Now also count down from center
|
|
i = startI + 1;
|
|
while (i < maxI && image[centerJ, i] && stateCount[1] <= maxCount)
|
|
{
|
|
stateCount[1]++;
|
|
i++;
|
|
}
|
|
if (i == maxI || stateCount[1] > maxCount)
|
|
{
|
|
return null;
|
|
}
|
|
while (i < maxI && !image[centerJ, i] && stateCount[2] <= maxCount)
|
|
{
|
|
stateCount[2]++;
|
|
i++;
|
|
}
|
|
if (stateCount[2] > maxCount)
|
|
{
|
|
return null;
|
|
}
|
|
|
|
int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2];
|
|
if (5 * Math.Abs(stateCountTotal - originalStateCountTotal) >= 2 * originalStateCountTotal)
|
|
{
|
|
return null;
|
|
}
|
|
|
|
return foundPatternCross(stateCount) ? centerFromEnd(stateCount, i) : null;
|
|
}
|
|
|
|
/// <summary> <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>
|
|
///
|
|
/// </summary>
|
|
/// <param name="stateCount">reading state module counts from horizontal scan
|
|
/// </param>
|
|
/// <param name="i">row where alignment pattern may be found
|
|
/// </param>
|
|
/// <param name="j">end of possible alignment pattern in row
|
|
/// </param>
|
|
/// <returns> {@link AlignmentPattern} if we have found the same pattern twice, or null if not
|
|
/// </returns>
|
|
private AlignmentPattern handlePossibleCenter(int[] stateCount, int i, int j)
|
|
{
|
|
int stateCountTotal = stateCount[0] + stateCount[1] + stateCount[2];
|
|
float? centerJ = centerFromEnd(stateCount, j);
|
|
if (centerJ == null)
|
|
return null;
|
|
float? centerI = crossCheckVertical(i, (int)centerJ, 2 * stateCount[1], stateCountTotal);
|
|
if (centerI != null)
|
|
{
|
|
float estimatedModuleSize = (stateCount[0] + stateCount[1] + stateCount[2]) / 3.0f;
|
|
foreach (var center in possibleCenters)
|
|
{
|
|
// Look for about the same center and module size:
|
|
if (center.aboutEquals(estimatedModuleSize, centerI.Value, centerJ.Value))
|
|
{
|
|
return center.combineEstimate(centerI.Value, centerJ.Value, estimatedModuleSize);
|
|
}
|
|
}
|
|
// Hadn't found this before; save it
|
|
var point = new AlignmentPattern(centerJ.Value, centerI.Value, estimatedModuleSize);
|
|
possibleCenters.Add(point);
|
|
if (resultPointCallback != null)
|
|
{
|
|
resultPointCallback(point);
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
}
|
|
} |
