WarpPI/teavm/src/main/java/ar/com/hjg/pngj/ImageLineSetDefault.java

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package ar.com.hjg.pngj;
import java.util.ArrayList;
import java.util.List;
/**
* Default implementation of {@link IImageLineSet}.
* <P>
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* Supports all modes: single cursor, full rows, or partial. This should not be
* used for
*/
public abstract class ImageLineSetDefault<T extends IImageLine> implements IImageLineSet<T> {
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protected final ImageInfo imgInfo;
private final boolean singleCursor;
private final int nlines, offset, step;
protected List<T> imageLines; // null if single cursor
protected T imageLine; // null unless single cursor
protected int currentRow = -1; // only relevant (and not much) for cursor
public ImageLineSetDefault(final ImageInfo imgInfo, final boolean singleCursor, final int nlinesx, final int noffsetx, final int stepx) {
this.imgInfo = imgInfo;
this.singleCursor = singleCursor;
if (singleCursor) {
this.nlines = 1; // we store only one line, no matter how many will be read
offset = 0;
this.step = 1;// don't matter
} else {
this.nlines = nlinesx; // note that it can also be 1
offset = noffsetx;
this.step = stepx;// don't matter
}
createImageLines();
}
private void createImageLines() {
if (singleCursor)
imageLine = createImageLine();
else {
imageLines = new ArrayList<>();
for (int i = 0; i < nlines; i++)
imageLines.add(createImageLine());
}
}
protected abstract T createImageLine();
/**
* Retrieves the image line
* <p>
* Warning: the argument is the row number in the original image
* <p>
* If this is a cursor, no check is done, always the same row is returned
*/
@Override
public T getImageLine(final int n) {
currentRow = n;
if (singleCursor)
return imageLine;
else {
final int r = imageRowToMatrixRowStrict(n);
if (r < 0)
throw new PngjException("Invalid row number");
return imageLines.get(r);
}
}
/**
* does not check for valid range
*/
@Override
public T getImageLineRawNum(final int r) {
if (singleCursor)
return imageLine;
else
return imageLines.get(r);
}
/**
* True if the set contains this image line
* <p>
* Warning: the argument is the row number in the original image
* <p>
* If this works as cursor, this returns true only if that is the number of
* its "current" line
*/
@Override
public boolean hasImageLine(final int n) {
return singleCursor ? currentRow == n : imageRowToMatrixRowStrict(n) >= 0;
}
/**
* How many lines does this object contain?
*/
@Override
public int size() {
return nlines;
}
/**
* Same as {@link #imageRowToMatrixRow(int)}, but returns negative if
* invalid
*/
public int imageRowToMatrixRowStrict(int imrow) {
imrow -= offset;
final int mrow = imrow >= 0 && (step == 1 || imrow % step == 0) ? imrow / step : -1;
return mrow < nlines ? mrow : -1;
}
/**
* Converts from matrix row number (0 : nRows-1) to image row number
*
* @param mrow
* Matrix row number
* @return Image row number. Returns trash if mrow is invalid
*/
public int matrixRowToImageRow(final int mrow) {
return mrow * step + offset;
}
/**
* Converts from real image row to this object row number.
* <p>
* Warning: this always returns a valid matrix row (clamping on 0 : nrows-1,
* and rounding down)
* <p>
* Eg: rowOffset=4,rowStep=2 imageRowToMatrixRow(17) returns 6 ,
* imageRowToMatrixRow(1) returns 0
*/
public int imageRowToMatrixRow(final int imrow) {
final int r = (imrow - offset) / step;
return r < 0 ? 0 : r < nlines ? r : nlines - 1;
}
/**
* utility function, given a factory for one line, returns a factory for a
* set
*/
public static <T extends IImageLine> IImageLineSetFactory<T> createImageLineSetFactoryFromImageLineFactory(
final IImageLineFactory<T> ifactory) { // ugly method must have ugly name. don't let this intimidate you
return (iminfo, singleCursor, nlines, noffset,
step) -> new ImageLineSetDefault<T>(iminfo, singleCursor, nlines, noffset, step) {
@Override
protected T createImageLine() {
return ifactory.createImageLine(iminfo);
}
};
}
/** utility function, returns default factory for {@link ImageLineInt} */
public static IImageLineSetFactory<ImageLineInt> getFactoryInt() {
return ImageLineSetDefault.createImageLineSetFactoryFromImageLineFactory(ImageLineInt.getFactory());
}
/** utility function, returns default factory for {@link ImageLineByte} */
public static IImageLineSetFactory<ImageLineByte> getFactoryByte() {
return ImageLineSetDefault.createImageLineSetFactoryFromImageLineFactory(ImageLineByte.getFactory());
}
}