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https://issues.apache.org/jira/browse/IMAGING-159?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14295899#comment-14295899
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Emmanuel Bourg commented on IMAGING-159:
----------------------------------------
I agree that we need something better than a Map for the parameters, something
that is typed and self documenting to make the API easier to use.
I experimented with an ImagingParams class that looked like this:
{code:java}
package org.apache.commons.imaging;
import org.apache.commons.imaging.common.IBufferedImageFactory;
public class ImagingParams {
private boolean verbose;
private boolean strict;
private String filename;
private IBufferedImageFactory bufferedImageFactory;
private PixelDensity pixelDensity;
public boolean isVerbose() {
return verbose;
}
public void setVerbose(boolean verbose) {
this.verbose = verbose;
}
/**
* Indicates whether to throw exceptions when parsing invalid
* files, or whether to tolerate small problems.
*/
public boolean isStrict() {
return strict;
}
public void setStrict(boolean strict) {
this.strict = strict;
}
public String getFilename() {
return filename;
}
/**
* Used to hint the filename when reading from a byte array
* or InputStream. The filename hint can help disambiguate what file the
* image format.
* <p>
* Applies to read operations.
*/
public void setFilename(String filename) {
this.filename = filename;
}
public IBufferedImageFactory getBufferedImageFactory() {
return bufferedImageFactory;
}
public void setBufferedImageFactory(IBufferedImageFactory
bufferedImageFactory) {
this.bufferedImageFactory = bufferedImageFactory;
}
public PixelDensity getPixelDensity() {
return pixelDensity;
}
/**
* Used in write operations to indicate the desired pixel
* density (DPI), and/or aspect ratio.
*/
public void setPixelDensity(PixelDensity pixelDensity) {
this.pixelDensity = pixelDensity;
}
}
{code}
The class contains only the common parameters, I wanted to build a class
hierarchy to specialize the parameters per format, but I haven't figured how to
modelize that properly.
> There should be a Parameters class
> ----------------------------------
>
> Key: IMAGING-159
> URL: https://issues.apache.org/jira/browse/IMAGING-159
> Project: Commons Imaging
> Issue Type: Improvement
> Components: imaging.*
> Reporter: Benedikt Ritter
> Fix For: Patch Needed
>
>
> Currently options for image I/O are defined as Maps. The leads to the problem
> that our code has to validate parameter types when they are used:
> {code:java}
> final Object value = params.get(PARAM_KEY_COMPRESSION);
> if (value != null) {
> if (!(value instanceof Number)) {
> throw new ImageWriteException(
> "Invalid compression parameter, must be numeric: "
> + value);
> }
> compression = ((Number) value).intValue();
> }
> {code}
> This can be simplified if we define a Parameters class that provides
> additional methods like {{public int getInt(String key)}}. The implementation
> could then look up the value from the map through an exception if it is null
> or not a number.
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