fix(holiday): 铁路客运量走势图10月3日标签上移避免遮挡

xyc

昨天 adee580f186d7f1cc5d5405792d6b0c13076f0a2

 traffic-audit-server/src/test/java/com/trafficaudit/holiday/service/HolidayTrendChartServiceTest.java

@@ -138,6 +138,64 @@
                "custom day labels should change the rendered axis");
    }

    @Test
    void pinsRequestedLineLabelToFixedAnchor() throws Exception {
        HolidayTrendChartService service = new HolidayTrendChartService();
        HolidayTrendChartService.ChartSeries series = new HolidayTrendChartService.ChartSeries();
        series.setName("2026\u5e74");
        series.setValues(java.util.Collections.singletonList(new BigDecimal("72.4")));
        java.util.List<HolidayTrendChartService.ChartSeries> single =
                java.util.Collections.singletonList(series);

        byte[] plain = service.lineChart("\u4e07\u4eba\u6b21", single, false, 2, 1100, 590);
        byte[] emptyOverrides = service.lineChart("\u4e07\u4eba\u6b21", single, false, 2,
                HolidayTrendChartService.DAY_LABELS, 1100, 590,
                java.util.Collections.emptyList());
        assertArrayEquals(plain, emptyOverrides,
                "an empty override list must keep the automatic placement");

        byte[] unmatched = service.lineChart("\u4e07\u4eba\u6b21", single, false, 2,
                HolidayTrendChartService.DAY_LABELS, 1100, 590,
                java.util.Collections.singletonList(new HolidayTrendChartService.LineLabelOverride(
                        0, 7, HolidayTrendChartService.LineLabelAnchor.ABOVE)));
        assertArrayEquals(plain, unmatched,
                "an override for a label that does not exist must not change rendering");

        byte[] above = service.lineChart("\u4e07\u4eba\u6b21", single, false, 2,
                HolidayTrendChartService.DAY_LABELS, 1100, 590,
                java.util.Collections.singletonList(new HolidayTrendChartService.LineLabelOverride(
                        0, 0, HolidayTrendChartService.LineLabelAnchor.ABOVE)));
        byte[] below = service.lineChart("\u4e07\u4eba\u6b21", single, false, 2,
                HolidayTrendChartService.DAY_LABELS, 1100, 590,
                java.util.Collections.singletonList(new HolidayTrendChartService.LineLabelOverride(
                        0, 0, HolidayTrendChartService.LineLabelAnchor.BELOW)));

        assertPng(above);
        assertPng(below);
        assertFalse(java.util.Arrays.equals(above, below),
                "ABOVE and BELOW anchors must render differently");
        assertTrue(meanSeriesColorY(above) < meanSeriesColorY(below),
                "the ABOVE anchor must place the label higher than the BELOW anchor");
    }

    private double meanSeriesColorY(byte[] data) throws Exception {
        BufferedImage image = ImageIO.read(new ByteArrayInputStream(data));
        assertNotNull(image);
        int target = 0xC0504D;
        long count = 0;
        long sum = 0;
        for (int y = 0; y < image.getHeight() - 60; y++) {
            for (int x = 0; x < image.getWidth(); x++) {
                if ((image.getRGB(x, y) & 0xFFFFFF) == target) {
                    count++;
                    sum += y;
                }
            }
        }
        assertTrue(count > 0, "expected series-coloured pixels for the item label");
        return (double) sum / count;
    }

    private void assertNoLargeLightGrayBackground(byte[] data) throws Exception {
        BufferedImage image = ImageIO.read(new ByteArrayInputStream(data));
        int matches = 0;