/**
* Constructor creates an instance to be used for fill operations.
*
* @param shading the shading type to be used
* @param colorModel the color model to be used
* @param xform transformation for user to device space
* @param matrix the pattern matrix concatenated with that of the parent content stream
* @param deviceBounds the bounds of the area to paint, in device units
* @throws IOException if there is an error getting the color space or doing color conversion.
*/
public AxialShadingContext(
PDShadingType2 shading,
ColorModel colorModel,
AffineTransform xform,
Matrix matrix,
Rectangle deviceBounds)
throws IOException {
super(shading, colorModel, xform, matrix);
this.axialShadingType = shading;
coords = shading.getCoords().toFloatArray();
// domain values
if (shading.getDomain() != null) {
domain = shading.getDomain().toFloatArray();
} else {
// set default values
domain = new float[] {0, 1};
}
// extend values
COSArray extendValues = shading.getExtend();
if (shading.getExtend() != null) {
extend = new boolean[2];
extend[0] = ((COSBoolean) extendValues.get(0)).getValue();
extend[1] = ((COSBoolean) extendValues.get(1)).getValue();
} else {
// set default values
extend = new boolean[] {false, false};
}
// calculate some constants to be used in getRaster
x1x0 = coords[2] - coords[0];
y1y0 = coords[3] - coords[1];
d1d0 = domain[1] - domain[0];
denom = Math.pow(x1x0, 2) + Math.pow(y1y0, 2);
try {
// get inverse transform to be independent of current user / device space
// when handling actual pixels in getRaster()
rat = matrix.createAffineTransform().createInverse();
rat.concatenate(xform.createInverse());
} catch (NoninvertibleTransformException ex) {
LOG.error(ex, ex);
}
// shading space -> device space
AffineTransform shadingToDevice = (AffineTransform) xform.clone();
shadingToDevice.concatenate(matrix.createAffineTransform());
// worst case for the number of steps is opposite diagonal corners, so use that
double dist =
Math.sqrt(
Math.pow(deviceBounds.getMaxX() - deviceBounds.getMinX(), 2)
+ Math.pow(deviceBounds.getMaxY() - deviceBounds.getMinY(), 2));
factor = (int) Math.ceil(dist);
// build the color table for the given number of steps
colorTable = calcColorTable();
}
/**
* Calculate the color on the axial line and store them in an array.
*
* @return an array, index denotes the relative position, the corresponding value is the color on
* the axial line
* @throws IOException if the color conversion fails.
*/
private int[] calcColorTable() throws IOException {
int[] map = new int[factor + 1];
if (factor == 0 || d1d0 == 0) {
float[] values = axialShadingType.evalFunction(domain[0]);
map[0] = convertToRGB(values);
} else {
for (int i = 0; i <= factor; i++) {
float t = domain[0] + d1d0 * i / factor;
float[] values = axialShadingType.evalFunction(t);
map[i] = convertToRGB(values);
}
}
return map;
}
/**
* Returns the function.
*
* @throws java.io.IOException if we were not able to create the function.
*/
public PDFunction getFunction() throws IOException {
return axialShadingType.getFunction();
}
