/**
* <p>Checks a set of points that have been transformed to sample points on an image against
- * the image's dimensions to see if the endpoints are even within the image.
- * This method actually only checks the endpoints since the points are assumed to lie
- * on a line.</p>
+ * the image's dimensions to see if the point are even within the image.</p>
*
* <p>This method will actually "nudge" the endpoints back onto the image if they are found to be barely
* (less than 1 pixel) off the image. This accounts for imperfect detection of finder patterns in an image
* where the QR Code runs all the way to the image border.</p>
*
+ * <p>For efficiency, the method will check points from either end of the line until one is found
+ * to be within the image. Because the set of points are assumed to be linear, this is valid.</p>
+ *
* @param image image into which the points should map
* @param points actual points in x1,y1,...,xn,yn form
* @throws ReaderException if an endpoint is lies outside the image boundaries
*/
- protected static void checkEndpoint(MonochromeBitmapSource image, float[] points) throws ReaderException {
+ protected static void checkAndNudgePoints(MonochromeBitmapSource image, float[] points) throws ReaderException {
int width = image.getWidth();
int height = image.getHeight();
- checkOneEndpoint(points, 0, width, height);
- checkOneEndpoint(points, points.length - 2, width, height);
- }
-
- private static void checkOneEndpoint(float[] points, int offset, int width, int height) throws ReaderException {
- int x = (int) points[offset];
- int y = (int) points[offset + 1];
- if (x < -1 || x > width || y < -1 || y > height) {
- throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
- }
- if (x == -1) {
- points[offset] = 0.0f;
- } else if (x == width) {
- points[offset] = width - 1;
+ // Check and nudge points from start until we see some that are OK:
+ boolean nudged = true;
+ for (int offset = 0; offset < points.length && nudged; offset += 2) {
+ int x = (int) points[offset];
+ int y = (int) points[offset + 1];
+ if (x < -1 || x > width || y < -1 || y > height) {
+ throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
+ }
+ nudged = false;
+ if (x == -1) {
+ points[offset] = 0.0f;
+ nudged = true;
+ } else if (x == width) {
+ points[offset] = width - 1;
+ nudged = true;
+ }
+ if (y == -1) {
+ points[offset + 1] = 0.0f;
+ nudged = true;
+ } else if (y == height) {
+ points[offset + 1] = height - 1;
+ nudged = true;
+ }
}
- if (y == -1) {
- points[offset + 1] = 0.0f;
- } else if (y == height) {
- points[offset + 1] = height - 1;
+ // Check and nudge points from end:
+ nudged = true;
+ for (int offset = points.length - 2; offset >= 0 && nudged; offset -= 2) {
+ int x = (int) points[offset];
+ int y = (int) points[offset + 1];
+ if (x < -1 || x > width || y < -1 || y > height) {
+ throw new ReaderException("Transformed point out of bounds at " + x + ',' + y);
+ }
+ nudged = false;
+ if (x == -1) {
+ points[offset] = 0.0f;
+ nudged = true;
+ } else if (x == width) {
+ points[offset] = width - 1;
+ nudged = true;
+ }
+ if (y == -1) {
+ points[offset + 1] = 0.0f;
+ nudged = true;
+ } else if (y == height) {
+ points[offset + 1] = height - 1;
+ nudged = true;
+ }
}
}