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jisedlacthurka
jisedlac
authored and
thurka
committed
GH-61 Prevent jumping charts for large amounts of displayed data
 - also improves performance and reduces memory allocations
1 parent f61d14c commit 7417b74

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-33
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+136
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‎visualvm/charts/src/com/sun/tools/visualvm/charts/xy/XYPainter.java

Lines changed: 136 additions & 33 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
/*
2-
* Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
2+
* Copyright (c) 2007, 2019, Oracle and/or its affiliates. All rights reserved.
33
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
44
*
55
* This code is free software; you can redistribute it and/or modify it
@@ -337,7 +337,7 @@ private int[][] getMinMaxPoints(XYItem item, Rectangle dirtyArea,
337337
double itemValueFactor = type == TYPE_RELATIVE ? getItemValueFactor(context,
338338
maxValueOffset, item.getBounds().height) : 0;
339339

340-
int maxPoints = Math.max(dirtyArea.width, (lastIndex - firstIndex + 1) * 3);
340+
int maxPoints = Math.min(dirtyArea.width * 4, lastIndex - firstIndex + 1);
341341

342342
int[] xPoints = new int[maxPoints + 2];
343343
int[] yPoints = new int[maxPoints + 2];
@@ -348,46 +348,149 @@ private int[][] getMinMaxPoints(XYItem item, Rectangle dirtyArea,
348348
int y = Utils.checkedInt(Math.ceil(getYValue(item, index,
349349
type, context, itemValueFactor)));
350350

351-
if (nPoints == 0) { // First point
352-
xPoints[nPoints] = x;
353-
yPoints[nPoints] = y;
354-
nPoints++;
355-
} else { // Other than first point
356-
int x_1 = xPoints[nPoints - 1];
351+
int nValues = 0;
352+
353+
if (nPoints > 0) {
354+
if (xPoints[nPoints - 1] == x) nValues = 1;
357355

358-
if (x_1 != x) { // New point
359-
xPoints[nPoints] = x;
360-
yPoints[nPoints] = y;
361-
nPoints++;
362-
} else { // Existing point
363-
int y_1 = yPoints[nPoints - 1];
356+
if (nPoints > 1) {
357+
if (xPoints[nPoints - 2] == x) nValues = 2;
364358

365-
if (nPoints > 1 && xPoints[nPoints - 2] == x_1) { // Existing point with two values
366-
int y_2 = yPoints[nPoints - 2];
367-
368-
int minY = Math.min(y, y_1);
369-
int maxY = Math.max(y, y_2);
359+
if (nPoints > 2) {
360+
if (xPoints[nPoints - 3] == x) nValues = 3;
370361

371-
yPoints[nPoints - 3] = minY;
372-
yPoints[nPoints - 2] = maxY;
373-
yPoints[nPoints - 1] = minY;
374-
} else { // Existing point with one value
375-
if (y_1 != y) { // Creating second value
376-
int minY = Math.min(y, y_1);
377-
int maxY = Math.max(y, y_1);
378-
379-
yPoints[nPoints - 1] = minY;
380-
362+
if (nPoints > 3) {
363+
if (xPoints[nPoints - 4] == x) nValues = 4;
364+
}
365+
}
366+
}
367+
}
368+
369+
switch (nValues) {
370+
// New point at X
371+
case 0:
372+
if (nPoints < 2 || yPoints[nPoints - 1] != y || yPoints[nPoints - 2] != y) { // first, second or new point, create it
373+
xPoints[nPoints] = x;
374+
yPoints[nPoints] = y;
375+
nPoints++;
376+
} else { // repeated point, collapse it
377+
xPoints[nPoints - 1] = x;
378+
}
379+
380+
break;
381+
382+
// Second point at X
383+
case 1:
384+
if (yPoints[nPoints - 1] != y) { // only add second point if its value differs from the first point
385+
xPoints[nPoints] = x;
386+
yPoints[nPoints] = y;
387+
nPoints++;
388+
}
389+
390+
break;
391+
392+
// Third point at X
393+
case 2:
394+
int y_1_2 = yPoints[nPoints - 1];
395+
if (y_1_2 != y) { // only add third point if its value differs from the second point
396+
if (yPoints[nPoints - 2] < y_1_2 && y_1_2 < y) { // new maximum value, collapse it
397+
yPoints[nPoints - 1] = y;
398+
} else if (yPoints[nPoints - 2] > y_1_2 && y_1_2 > y) { // new minimum value, collapse it
399+
yPoints[nPoints - 1] = y;
400+
} else { // new end value, create it
381401
xPoints[nPoints] = x;
382-
yPoints[nPoints] = maxY;
402+
yPoints[nPoints] = y;
383403
nPoints++;
384-
404+
}
405+
}
406+
407+
break;
408+
409+
// Fourth point at X
410+
case 3:
411+
int y_1_3 = yPoints[nPoints - 1];
412+
if (y_1_3 != y) { // only add fourth point if its value differs from the third point
413+
int y_2_3 = yPoints[nPoints - 2];
414+
int y_3_3 = yPoints[nPoints - 3];
415+
416+
int min = y;
417+
int max = y;
418+
419+
if (y_1_3 < min) min = y_1_3;
420+
else if (y_1_3 > max) max = y_1_3;
421+
422+
if (y_2_3 < min) min = y_2_3;
423+
else if (y_2_3 > max) max = y_2_3;
424+
425+
if (y_3_3 < min) min = y_3_3;
426+
else if (y_3_3 > max) max = y_3_3;
427+
428+
if (y == min) {
429+
if (y_3_3 == max) {
430+
yPoints[nPoints - 2] = y;
431+
nPoints--;
432+
} else {
433+
yPoints[nPoints - 2] = max;
434+
yPoints[nPoints - 1] = y;
435+
}
436+
} else if (y == max) {
437+
if (y_3_3 == min) {
438+
yPoints[nPoints - 2] = y;
439+
nPoints--;
440+
} else {
441+
yPoints[nPoints - 2] = min;
442+
yPoints[nPoints - 1] = y;
443+
}
444+
} else if (y_3_3 == min) {
445+
yPoints[nPoints - 2] = max;
446+
yPoints[nPoints - 1] = y;
447+
} else if (y_3_3 == max) {
448+
yPoints[nPoints - 2] = min;
449+
yPoints[nPoints - 1] = y;
450+
} else {
385451
xPoints[nPoints] = x;
386-
yPoints[nPoints] = minY;
452+
yPoints[nPoints] = y;
387453
nPoints++;
388454
}
389455
}
390-
}
456+
457+
break;
458+
459+
// Another point at X
460+
case 4:
461+
int y_1_4 = yPoints[nPoints - 1];
462+
if (y_1_4 != y) { // only add another point if its value differs from the fourth point
463+
int y_2_4 = yPoints[nPoints - 2];
464+
int y_3_4 = yPoints[nPoints - 3];
465+
int y_4_4 = yPoints[nPoints - 4];
466+
467+
int min = y;
468+
int max = y;
469+
470+
if (y_1_4 < min) min = y_1_4;
471+
else if (y_1_4 > max) max = y_1_4;
472+
473+
if (y_2_4 < min) min = y_2_4;
474+
else if (y_2_4 > max) max = y_2_4;
475+
476+
if (y_3_4 < min) min = y_3_4;
477+
else if (y_3_4 > max) max = y_3_4;
478+
479+
if (y_4_4 < min) min = y_4_4;
480+
else if (y_4_4 > max) max = y_4_4;
481+
482+
if (y == min) {
483+
yPoints[nPoints - 3] = max;
484+
yPoints[nPoints - 2] = y;
485+
nPoints--;
486+
} else if (y == max) {
487+
yPoints[nPoints - 3] = min;
488+
yPoints[nPoints - 2] = y;
489+
nPoints--;
490+
} else {
491+
yPoints[nPoints - 1] = y;
492+
}
493+
}
391494
}
392495
}
393496

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