我正在尝试使用以下代码生成图表并通过休息响应进行渲染。
Application class
@SpringBootApplication
@EnableWebMvc
@EnableWebSecurity
public class JChartPoc extends WebSecurityConfigurerAdapter{
public static void main(String[] args) {
SpringApplication.run(JChartPoc.class, args);
}
@Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.antMatchers("/**").permitAll()
.and()
.csrf().disable();
}
}
图表在尺寸 500x500 下渲染得非常好,但我有一个限制将图像渲染为 352 x 90。
我在
中使用以下代码生成了折线图Controller class.
@RestController
public class LineChartController {
@RequestMapping(value = "chartsPNG", method = RequestMethod.GET, produces = MediaType.IMAGE_PNG_VALUE)
public ResponseEntity<byte[]> getPNGChart(@RequestHeader HttpHeaders headers)
throws Exception {
List<String> acceptLanguageList = headers
.get(HttpHeaders.ACCEPT_LANGUAGE);
String acceptLanguage = acceptLanguageList.get(0);
if (acceptLanguage.equalsIgnoreCase("en-us")) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ChartUtilities.writeBufferedImageAsPNG(baos, createLineChart().createBufferedImage(380, 90));
return new ResponseEntity<byte[]>(baos.toByteArray(), HttpStatus.OK);
}
return new ResponseEntity<byte[]>("Language Not Supported".getBytes(),
HttpStatus.I_AM_A_TEAPOT);
}
private JFreeChart createLineChart() {
DefaultCategoryDataset lineDataSet = new DefaultCategoryDataset();
lineDataSet.setValue(122, "weekly", "3 Weeks Ago");
lineDataSet.setValue(200, "weekly", "2 Weeks Ago");
lineDataSet.setValue(246, "weekly", "1 Week Ago");
lineDataSet.setValue(348, "weekly", "This Week");
JFreeChart lineChart = ChartFactory.createLineChart(null, null, null,lineDataSet);
modifyChart(lineChart);
return lineChart;
}
protected void modifyChart(JFreeChart chart) {
// plot manipulations
CategoryPlot categoryPlotModifier = chart.getCategoryPlot();
categoryPlotModifier.getRangeAxis().setTickLabelsVisible(false);
categoryPlotModifier.setOutlineVisible(false);
categoryPlotModifier.getRangeAxis().setVisible(false);
categoryPlotModifier.getDomainAxis().setTickMarkInsideLength(10);
categoryPlotModifier.getDomainAxis().setCategoryLabelPositionOffset(6);
categoryPlotModifier.getDomainAxis().setLabelFont(
new Font("SansSerif", Font.PLAIN, 100));
categoryPlotModifier.setAxisOffset(new RectangleInsets());
// categoryPlotModifier.getRangeAxis().resizeRange(500.);
// change fonts on charts
categoryPlotModifier.setBackgroundPaint(Color.WHITE);
LineAndShapeRenderer renderer = (LineAndShapeRenderer) categoryPlotModifier
.getRenderer();
renderer.setBaseShape(new Polygon(), true);
renderer.setBaseFillPaint(Color.WHITE, true);
renderer.setBaseShapesVisible(true);
renderer.setDrawOutlines(true);
renderer.setUseFillPaint(true);
// renderer.setSeriesStroke(0, new BasicStroke(1), true);
CategoryItemLabelGenerator labelGenerator = new StandardCategoryItemLabelGenerator(
"{2}", new DecimalFormat("0.00"));
renderer.setBaseItemLabelGenerator(labelGenerator);
renderer.setBaseItemLabelsVisible(true, true);
// renderer.setBasePaint(Color.GREEN, true);
// why not baseColor and why can't we change the color of individual
// series
renderer.setSeriesPaint(0, ChartColor.VERY_DARK_MAGENTA, true);
// logger.info(Boolean.toString(renderer.getBaseShapesVisible()));
chart.removeLegend();
}
}
Controller 中的这一行控制用于渲染的尺寸
ChartUtilities.writeBufferedImageAsPNG(baos,createLineChart().createBufferedImage(380, 90));
有没有办法调整图表大小以渲染为 352 x 90 PNG 图像,该图像不会被模糊但可以正确调整大小?
最佳答案
@trashgod 建议的 setUpperMargin() 后的解决方案。我确信有一种编程方法可以计算 setUpperMargin 函数所需的值,如果我实现它,我将更新这个答案。
@RestController
public class LineChartController {
@RequestMapping(value = "chartsPNG", method = RequestMethod.GET, produces = MediaType.IMAGE_PNG_VALUE)
public ResponseEntity<byte[]> getPNGChart(@RequestHeader HttpHeaders headers)
throws Exception {
List<String> acceptLanguageList = headers
.get(HttpHeaders.ACCEPT_LANGUAGE);
String acceptLanguage = acceptLanguageList.get(0);
if (acceptLanguage.equalsIgnoreCase("en-us")) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ChartUtilities.writeBufferedImageAsPNG(baos, createLineChart().createBufferedImage(352, 90));
return new ResponseEntity<byte[]>(baos.toByteArray(), HttpStatus.OK);
}
return new ResponseEntity<byte[]>("Language Not Supported".getBytes(),
HttpStatus.I_AM_A_TEAPOT);
}
private JFreeChart createLineChart() {
DefaultCategoryDataset lineDataSet = new DefaultCategoryDataset();
lineDataSet.setValue(122, "weekly", "3 Weeks Ago");
lineDataSet.setValue(200, "weekly", "2 Weeks Ago");
lineDataSet.setValue(246, "weekly", "1 Week Ago");
lineDataSet.setValue(348, "weekly", "This Week");
JFreeChart lineChart = ChartFactory.createLineChart(null, null, null,lineDataSet);
modifyChart(lineChart);
return lineChart;
}
protected void modifyChart(JFreeChart chart) {
Color lineChartColor = new Color(40, 54, 67);
// plot manipulations
CategoryPlot categoryPlotModifier = chart.getCategoryPlot();
categoryPlotModifier.setOutlineVisible(false);
categoryPlotModifier.setBackgroundPaint(Color.WHITE);
//Axis modifications
categoryPlotModifier.getRangeAxis().setVisible(false);
categoryPlotModifier.getDomainAxis().setTickMarkInsideLength(10);
categoryPlotModifier.getDomainAxis().setLabelFont(new Font("SansSerif", Font.PLAIN, 1));
//Needed to avoid truncation of plot and squeeze of category label name during resized rendering (352X90)
categoryPlotModifier.getRangeAxis().setUpperMargin(.5);
categoryPlotModifier.getDomainAxis().setCategoryMargin(.02);
// Actual data point manipulations
LineAndShapeRenderer renderer = (LineAndShapeRenderer) categoryPlotModifier.getRenderer();
renderer.setSeriesShape(0,new Ellipse2D.Double(-3, -3, 6, 6), true);
renderer.setBaseFillPaint(lineChartColor, true);
renderer.setBaseShapesVisible(true);
renderer.setDrawOutlines(true);
renderer.setUseFillPaint(true);
CategoryItemLabelGenerator labelGenerator = new StandardCategoryItemLabelGenerator("{2}", new DecimalFormat("0.00"));
renderer.setBaseItemLabelGenerator(labelGenerator);
renderer.setBaseItemLabelsVisible(true, true);
/*renderer.setBasePaint(Color.GREEN, true);
// why doesn't setBasePaint change the color of all shapes and lines
* in data points and why can't we change the color of individual series
*/
renderer.setSeriesPaint(0, lineChartColor, true);
// logger.info(Boolean.toString(renderer.getBaseShapesVisible()));
chart.removeLegend();
}
}
关于java - 如何在编码为 PNG 之前调整 JFreeChart 的大小,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40895571/