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JUCE/modules/juce_graphics/geometry/juce_EdgeTable.cpp
reuk ce0fe3dc1e
EdgeTable: Keep better track of buffer memory ranges
Occasionally, on Linux, Address Sanitizer can complain about a memory
region overlap in the arguments to memcpy, originating in
EdgeTable::intersectWithEdgeTableLine. I haven't been able to reproduce
this personally.

The final memcpy call in this function requires there to be
"srcNum1 * 2" valid entries after the current "src1" ptr, and none of
those entries may overlap with the area starting at "temp".

On inspection, I think that the memory region being read is too large.
At the point of the call, src1 will point to a LineItem::level, not
LineItem::x, so there will actually be (srcNum1 * 2 - 1) valid items
following it.

All this pointer arithmetic is very difficult to understand. In an
effort to make this function slightly more understandable, I've switched
to using Spans to delineate lines of the table, which makes it easier to
keep track of the size of each line.
2024-05-20 12:49:55 +01:00

848 lines
24 KiB
C++

/*
==============================================================================
This file is part of the JUCE framework.
Copyright (c) Raw Material Software Limited
JUCE is an open source framework subject to commercial or open source
licensing.
By downloading, installing, or using the JUCE framework, or combining the
JUCE framework with any other source code, object code, content or any other
copyrightable work, you agree to the terms of the JUCE End User Licence
Agreement, and all incorporated terms including the JUCE Privacy Policy and
the JUCE Website Terms of Service, as applicable, which will bind you. If you
do not agree to the terms of these agreements, we will not license the JUCE
framework to you, and you must discontinue the installation or download
process and cease use of the JUCE framework.
JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
JUCE Privacy Policy: https://juce.com/juce-privacy-policy
JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/
Or:
You may also use this code under the terms of the AGPLv3:
https://www.gnu.org/licenses/agpl-3.0.en.html
THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
==============================================================================
*/
namespace juce
{
JUCE_BEGIN_IGNORE_WARNINGS_MSVC (6255 6263 6386)
EdgeTable::EdgeTable (Rectangle<int> area, const Path& path, const AffineTransform& transform)
: bounds (area),
// this is a very vague heuristic to make a rough guess at a good table size
// for a given path, such that it's big enough to mostly avoid remapping, but also
// not so big that it's wasteful for simple paths.
maxEdgesPerLine (jmax (defaultEdgesPerLine / 2,
4 * (int) std::sqrt (path.data.size()))),
lineStrideElements (maxEdgesPerLine * 2 + 1)
{
allocate();
int* t = table.data();
for (int i = bounds.getHeight(); --i >= 0;)
{
*t = 0;
t += lineStrideElements;
}
auto leftLimit = scale * static_cast<int64_t> (bounds.getX());
auto topLimit = scale * static_cast<int64_t> (bounds.getY());
auto rightLimit = scale * static_cast<int64_t> (bounds.getRight());
auto heightLimit = scale * static_cast<int64_t> (bounds.getHeight());
PathFlatteningIterator iter (path, transform);
while (iter.next())
{
const auto scaleIterY = [] (auto y)
{
return static_cast<int64_t> (y * 256.0f + (y >= 0 ? 0.5f : -0.5f));
};
auto y1 = scaleIterY (iter.y1);
auto y2 = scaleIterY (iter.y2);
if (y1 != y2)
{
y1 -= topLimit;
y2 -= topLimit;
auto startY = y1;
int direction = -1;
if (y1 > y2)
{
std::swap (y1, y2);
direction = 1;
}
if (y1 < 0)
y1 = 0;
if (y2 > heightLimit)
y2 = heightLimit;
if (y1 < y2)
{
const double startX = 256.0f * iter.x1;
const double multiplier = (iter.x2 - iter.x1) / (iter.y2 - iter.y1);
auto stepSize = static_cast<int64_t> (jlimit (1, 256, 256 / (1 + (int) std::abs (multiplier))));
do
{
auto step = jmin (stepSize, y2 - y1, 256 - (y1 & 255));
auto x = static_cast<int64_t> (startX + multiplier * static_cast<double> ((y1 + (step >> 1)) - startY));
auto clampedX = static_cast<int> (jlimit (leftLimit, rightLimit - 1, x));
addEdgePoint (clampedX, static_cast<int> (y1 / scale), static_cast<int> (direction * step));
y1 += step;
}
while (y1 < y2);
}
}
}
sanitiseLevels (path.isUsingNonZeroWinding());
}
EdgeTable::EdgeTable (Rectangle<int> rectangleToAdd)
: bounds (rectangleToAdd),
maxEdgesPerLine (defaultEdgesPerLine),
lineStrideElements (defaultEdgesPerLine * 2 + 1)
{
allocate();
table[0] = 0;
auto x1 = scale * rectangleToAdd.getX();
auto x2 = scale * rectangleToAdd.getRight();
int* t = table.data();
for (int i = rectangleToAdd.getHeight(); --i >= 0;)
{
t[0] = 2;
t[1] = x1;
t[2] = 255;
t[3] = x2;
t[4] = 0;
t += lineStrideElements;
}
}
EdgeTable::EdgeTable (const RectangleList<int>& rectanglesToAdd)
: bounds (rectanglesToAdd.getBounds()),
maxEdgesPerLine (defaultEdgesPerLine),
lineStrideElements (defaultEdgesPerLine * 2 + 1),
needToCheckEmptiness (true)
{
allocate();
clearLineSizes();
for (auto& r : rectanglesToAdd)
{
auto x1 = scale * r.getX();
auto x2 = scale * r.getRight();
auto y = r.getY() - bounds.getY();
for (int j = r.getHeight(); --j >= 0;)
addEdgePointPair (x1, x2, y++, 255);
}
sanitiseLevels (true);
}
EdgeTable::EdgeTable (const RectangleList<float>& rectanglesToAdd)
: bounds (rectanglesToAdd.getBounds().getSmallestIntegerContainer()),
maxEdgesPerLine (rectanglesToAdd.getNumRectangles() * 2),
lineStrideElements (rectanglesToAdd.getNumRectangles() * 4 + 1)
{
bounds.setHeight (bounds.getHeight() + 1);
allocate();
clearLineSizes();
for (auto& r : rectanglesToAdd)
{
auto x1 = roundToInt ((float) scale * r.getX());
auto x2 = roundToInt ((float) scale * r.getRight());
auto y1 = roundToInt ((float) scale * r.getY()) - (bounds.getY() * scale);
auto y2 = roundToInt ((float) scale * r.getBottom()) - (bounds.getY() * scale);
if (x2 <= x1 || y2 <= y1)
continue;
auto y = y1 / scale;
auto lastLine = y2 / scale;
if (y == lastLine)
{
addEdgePointPair (x1, x2, y, y2 - y1);
}
else
{
addEdgePointPair (x1, x2, y++, 255 - (y1 & 255));
while (y < lastLine)
addEdgePointPair (x1, x2, y++, 255);
jassert (y < bounds.getHeight());
addEdgePointPair (x1, x2, y, y2 & 255);
}
}
sanitiseLevels (true);
}
EdgeTable::EdgeTable (Rectangle<float> rectangleToAdd)
: bounds ((int) std::floor (rectangleToAdd.getX()),
roundToInt (rectangleToAdd.getY() * 256.0f) / scale,
2 + (int) rectangleToAdd.getWidth(),
2 + (int) rectangleToAdd.getHeight()),
maxEdgesPerLine (defaultEdgesPerLine),
lineStrideElements ((defaultEdgesPerLine * 2) + 1)
{
jassert (! rectangleToAdd.isEmpty());
allocate();
table[0] = 0;
auto x1 = roundToInt ((float) scale * rectangleToAdd.getX());
auto x2 = roundToInt ((float) scale * rectangleToAdd.getRight());
auto y1 = roundToInt ((float) scale * rectangleToAdd.getY()) - (bounds.getY() * scale);
auto y2 = roundToInt ((float) scale * rectangleToAdd.getBottom()) - (bounds.getY() * scale);
jassert (y1 < 256);
if (x2 <= x1 || y2 <= y1)
{
bounds.setHeight (0);
return;
}
int lineY = 0;
int* t = table.data();
if ((y1 / scale) == (y2 / scale))
{
t[0] = 2;
t[1] = x1;
t[2] = y2 - y1;
t[3] = x2;
t[4] = 0;
++lineY;
t += lineStrideElements;
}
else
{
t[0] = 2;
t[1] = x1;
t[2] = 255 - (y1 & 255);
t[3] = x2;
t[4] = 0;
++lineY;
t += lineStrideElements;
while (lineY < (y2 / scale))
{
t[0] = 2;
t[1] = x1;
t[2] = 255;
t[3] = x2;
t[4] = 0;
++lineY;
t += lineStrideElements;
}
jassert (lineY < bounds.getHeight());
t[0] = 2;
t[1] = x1;
t[2] = y2 & 255;
t[3] = x2;
t[4] = 0;
++lineY;
t += lineStrideElements;
}
while (lineY < bounds.getHeight())
{
t[0] = 0;
t += lineStrideElements;
++lineY;
}
}
//==============================================================================
static size_t getEdgeTableAllocationSize (int lineStride, int height) noexcept
{
// (leave an extra line at the end for use as scratch space)
return (size_t) (lineStride * (2 + jmax (0, height)));
}
void EdgeTable::allocate()
{
table.resize (getEdgeTableAllocationSize (lineStrideElements, bounds.getHeight()));
}
void EdgeTable::clearLineSizes() noexcept
{
int* t = table.data();
for (int i = bounds.getHeight(); --i >= 0;)
{
*t = 0;
t += lineStrideElements;
}
}
void EdgeTable::sanitiseLevels (const bool useNonZeroWinding) noexcept
{
// Convert the table from relative windings to absolute levels..
int* lineStart = table.data();
for (int y = bounds.getHeight(); --y >= 0;)
{
auto num = lineStart[0];
if (num > 0)
{
auto* items = reinterpret_cast<LineItem*> (lineStart + 1);
auto* itemsEnd = items + num;
// sort the X coords
std::sort (items, itemsEnd);
auto* src = items;
auto correctedNum = num;
int level = 0;
while (src < itemsEnd)
{
level += src->level;
auto x = src->x;
++src;
while (src < itemsEnd && src->x == x)
{
level += src->level;
++src;
--correctedNum;
}
auto corrected = std::abs (level);
if (corrected / scale)
{
if (useNonZeroWinding)
{
corrected = 255;
}
else
{
corrected &= 511;
if (corrected / scale)
corrected = 511 - corrected;
}
}
items->x = x;
items->level = corrected;
++items;
}
lineStart[0] = correctedNum;
(items - 1)->level = 0; // force the last level to 0, just in case something went wrong in creating the table
}
lineStart += lineStrideElements;
}
}
static void copyEdgeTableData (int* dest,
size_t destLineStride,
const int* src,
size_t srcLineStride,
size_t numLines) noexcept
{
for (size_t line = 0; line < numLines; ++line)
{
const auto* srcLine = src + line * srcLineStride;
std::copy (srcLine, srcLine + *srcLine * 2 + 1, dest + line * destLineStride);
}
}
void EdgeTable::remapTableForNumEdges (const int newNumEdgesPerLine)
{
if (newNumEdgesPerLine != maxEdgesPerLine)
{
jassert (newNumEdgesPerLine > maxEdgesPerLine);
maxEdgesPerLine = newNumEdgesPerLine;
jassert (bounds.getHeight() > 0);
auto newLineStrideElements = maxEdgesPerLine * 2 + 1;
std::vector<int> newTable (getEdgeTableAllocationSize (newLineStrideElements, bounds.getHeight()));
copyEdgeTableData (newTable.data(),
(size_t) newLineStrideElements,
table.data(),
(size_t) lineStrideElements,
(size_t) bounds.getHeight());
table = std::move (newTable);
lineStrideElements = newLineStrideElements;
}
}
inline void EdgeTable::remapWithExtraSpace (int numPoints)
{
remapTableForNumEdges (numPoints * 2);
jassert (numPoints < maxEdgesPerLine);
}
void EdgeTable::optimiseTable()
{
int maxLineElements = 0;
for (int i = bounds.getHeight(); --i >= 0;)
maxLineElements = jmax (maxLineElements, table[(size_t) i * (size_t) lineStrideElements]);
remapTableForNumEdges (maxLineElements);
}
void EdgeTable::addEdgePoint (const int x, const int y, const int winding)
{
jassert (y >= 0 && y < bounds.getHeight());
auto* line = table.data() + lineStrideElements * y;
auto numPoints = line[0];
if (numPoints >= maxEdgesPerLine)
{
remapWithExtraSpace (numPoints);
line = table.data() + lineStrideElements * y;
}
line[0] = numPoints + 1;
line += numPoints * 2;
line[1] = x;
line[2] = winding;
}
void EdgeTable::addEdgePointPair (int x1, int x2, int y, int winding)
{
jassert (y >= 0 && y < bounds.getHeight());
auto* line = table.data() + lineStrideElements * y;
auto numPoints = line[0];
if (numPoints + 1 >= maxEdgesPerLine)
{
remapWithExtraSpace (numPoints + 1);
line = table.data() + lineStrideElements * y;
}
line[0] = numPoints + 2;
line += numPoints * 2;
line[1] = x1;
line[2] = winding;
line[3] = x2;
line[4] = -winding;
}
void EdgeTable::translate (float dx, int dy) noexcept
{
bounds.translate ((int) std::floor (dx), dy);
int* lineStart = table.data();
auto intDx = (int) (dx * 256.0f);
for (int i = bounds.getHeight(); --i >= 0;)
{
auto* line = lineStart;
lineStart += lineStrideElements;
auto num = *line++;
while (--num >= 0)
{
*line += intDx;
line += 2;
}
}
}
void EdgeTable::multiplyLevels (float amount)
{
int* lineStart = table.data();
auto multiplier = (int) (amount * 256.0f);
for (int y = 0; y < bounds.getHeight(); ++y)
{
auto numPoints = lineStart[0];
auto* item = reinterpret_cast<LineItem*> (lineStart + 1);
lineStart += lineStrideElements;
while (--numPoints > 0)
{
item->level = jmin (255, (item->level * multiplier) / scale);
++item;
}
}
}
void EdgeTable::intersectWithEdgeTableLine (const int y, const int* const otherLine)
{
jassert (y >= 0 && y < bounds.getHeight());
auto* srcLine = table.data() + lineStrideElements * y;
const auto srcNum1 = *srcLine;
if (srcNum1 == 0)
return;
const auto srcNum2 = *otherLine;
if (srcNum2 == 0)
{
*srcLine = 0;
return;
}
Span srcLine1 { srcLine + 1, (size_t) srcNum1 * 2 };
Span srcLine2 { otherLine + 1, (size_t) srcNum2 * 2 };
const auto popHead = [] (auto& s)
{
if (s.empty())
return 0;
const auto result = s.front();
s = Span { s.data() + 1, s.size() - 1 };
return result;
};
const auto reseat = [] (auto& s, auto* ptr)
{
s = Span { ptr, s.size() };
};
const auto right = bounds.getRight() * scale;
// optimise for the common case where our line lies entirely within a
// single pair of points, as happens when clipping to a simple rect.
if (srcLine2.size() == 4 && srcLine2[1] >= 255)
{
clipEdgeTableLineToRange (srcLine, srcLine2[0], jmin (right, srcLine2[2]));
return;
}
bool isUsingTempSpace = false;
auto x1 = popHead (srcLine1);
auto x2 = popHead (srcLine2);
int destIndex = 0, destTotal = 0;
int level1 = 0, level2 = 0;
int lastX = std::numeric_limits<int>::min(), lastLevel = 0;
while (! srcLine1.empty() && ! srcLine2.empty())
{
int nextX;
if (x1 <= x2)
{
if (x1 == x2)
{
level2 = popHead (srcLine2);
x2 = popHead (srcLine2);
}
nextX = x1;
level1 = popHead (srcLine1);
x1 = popHead (srcLine1);
}
else
{
nextX = x2;
level2 = popHead (srcLine2);
x2 = popHead (srcLine2);
}
if (lastX < nextX)
{
if (right <= nextX)
break;
lastX = nextX;
auto nextLevel = (level1 * (level2 + 1)) / scale;
jassert (isPositiveAndBelow (nextLevel, 256));
if (nextLevel != lastLevel)
{
if (destTotal >= maxEdgesPerLine)
{
srcLine[0] = destTotal;
if (isUsingTempSpace)
{
auto* stackBuffer = static_cast<int*> (alloca (sizeof (int) * srcLine1.size()));
std::copy (srcLine1.begin(), srcLine1.end(), stackBuffer);
remapTableForNumEdges (jmax (256, destTotal * 2));
srcLine = table.data() + lineStrideElements * y;
reseat (srcLine1, table.data() + lineStrideElements * bounds.getHeight());
std::copy (stackBuffer, stackBuffer + srcLine1.size(), srcLine1.data());
}
else
{
remapTableForNumEdges (jmax (256, destTotal * 2));
srcLine = table.data() + lineStrideElements * y;
}
}
++destTotal;
lastLevel = nextLevel;
if (! isUsingTempSpace)
{
isUsingTempSpace = true;
auto* temp = table.data() + lineStrideElements * bounds.getHeight();
std::copy (srcLine1.begin(), srcLine1.end(), temp);
reseat (srcLine1, temp);
}
srcLine[++destIndex] = nextX;
srcLine[++destIndex] = nextLevel;
}
}
}
if (lastLevel > 0)
{
if (destTotal >= maxEdgesPerLine)
{
srcLine[0] = destTotal;
remapTableForNumEdges (jmax (256, destTotal * 2));
srcLine = table.data() + lineStrideElements * y;
}
++destTotal;
srcLine[++destIndex] = right;
srcLine[++destIndex] = 0;
}
srcLine[0] = destTotal;
}
void EdgeTable::clipEdgeTableLineToRange (int* dest, const int x1, const int x2) noexcept
{
int* lastItem = dest + (dest[0] * 2 - 1);
if (x2 < lastItem[0])
{
if (x2 <= dest[1])
{
dest[0] = 0;
return;
}
while (x2 < lastItem[-2])
{
--(dest[0]);
lastItem -= 2;
}
lastItem[0] = x2;
lastItem[1] = 0;
}
if (x1 > dest[1])
{
while (lastItem[0] > x1)
lastItem -= 2;
auto itemsRemoved = (int) (lastItem - (dest + 1)) / 2;
if (itemsRemoved > 0)
{
dest[0] -= itemsRemoved;
memmove (dest + 1, lastItem, (size_t) dest[0] * (sizeof (int) * 2));
}
dest[1] = x1;
}
}
//==============================================================================
void EdgeTable::clipToRectangle (Rectangle<int> r)
{
auto clipped = r.getIntersection (bounds);
if (clipped.isEmpty())
{
needToCheckEmptiness = false;
bounds.setHeight (0);
}
else
{
auto top = clipped.getY() - bounds.getY();
auto bottom = clipped.getBottom() - bounds.getY();
if (bottom < bounds.getHeight())
bounds.setHeight (bottom);
for (int i = 0; i < top; ++i)
table[(size_t) lineStrideElements * (size_t) i] = 0;
if (clipped.getX() > bounds.getX() || clipped.getRight() < bounds.getRight())
{
auto x1 = scale * clipped.getX();
auto x2 = scale * jmin (bounds.getRight(), clipped.getRight());
int* line = table.data() + lineStrideElements * top;
for (int i = bottom - top; --i >= 0;)
{
if (line[0] != 0)
clipEdgeTableLineToRange (line, x1, x2);
line += lineStrideElements;
}
}
needToCheckEmptiness = true;
}
}
void EdgeTable::excludeRectangle (Rectangle<int> r)
{
auto clipped = r.getIntersection (bounds);
if (! clipped.isEmpty())
{
auto top = clipped.getY() - bounds.getY();
auto bottom = clipped.getBottom() - bounds.getY();
const int rectLine[] = { 4, std::numeric_limits<int>::min(), 255,
scale * clipped.getX(), 0,
scale * clipped.getRight(), 255,
std::numeric_limits<int>::max(), 0 };
for (int i = top; i < bottom; ++i)
intersectWithEdgeTableLine (i, rectLine);
needToCheckEmptiness = true;
}
}
void EdgeTable::clipToEdgeTable (const EdgeTable& other)
{
auto clipped = other.bounds.getIntersection (bounds);
if (clipped.isEmpty())
{
needToCheckEmptiness = false;
bounds.setHeight (0);
}
else
{
auto top = clipped.getY() - bounds.getY();
auto bottom = clipped.getBottom() - bounds.getY();
if (bottom < bounds.getHeight())
bounds.setHeight (bottom);
if (clipped.getRight() < bounds.getRight())
bounds.setRight (clipped.getRight());
for (int i = 0; i < top; ++i)
table[(size_t) lineStrideElements * (size_t) i] = 0;
auto* otherLine = other.table.data() + other.lineStrideElements * (clipped.getY() - other.bounds.getY());
for (int i = top; i < bottom; ++i)
{
intersectWithEdgeTableLine (i, otherLine);
otherLine += other.lineStrideElements;
}
needToCheckEmptiness = true;
}
}
void EdgeTable::clipLineToMask (int x, int y, const uint8* mask, int maskStride, int numPixels)
{
y -= bounds.getY();
if (y < 0 || y >= bounds.getHeight())
return;
needToCheckEmptiness = true;
if (numPixels <= 0)
{
table[(size_t) lineStrideElements * (size_t) y] = 0;
return;
}
auto* tempLine = static_cast<int*> (alloca ((size_t) (numPixels * 2 + 4) * sizeof (int)));
int destIndex = 0, lastLevel = 0;
while (--numPixels >= 0)
{
auto alpha = *mask;
mask += maskStride;
if (alpha != lastLevel)
{
tempLine[++destIndex] = (x * scale);
tempLine[++destIndex] = alpha;
lastLevel = alpha;
}
++x;
}
if (lastLevel > 0)
{
tempLine[++destIndex] = (x * scale);
tempLine[++destIndex] = 0;
}
tempLine[0] = destIndex >> 1;
intersectWithEdgeTableLine (y, tempLine);
}
bool EdgeTable::isEmpty() noexcept
{
if (needToCheckEmptiness)
{
needToCheckEmptiness = false;
int* t = table.data();
for (int i = bounds.getHeight(); --i >= 0;)
{
if (t[0] > 1)
return false;
t += lineStrideElements;
}
bounds.setHeight (0);
}
return bounds.getHeight() == 0;
}
JUCE_END_IGNORE_WARNINGS_MSVC
} // namespace juce