Add createTJunctionFreeRegion
T-junction free regions are useful for rendering regions with various geometric transformations, and the Region's span-ordered, sorted rect list supports T-junction free storage without modification. This approach creates a T-junction free region by splitting each rectangle that is part of a vertical T-junction. This approach is two pass (up and down) so that divisions can trickle up/down to other adjacent spans. Change-Id: Ifcf5e6fe0034c96b00ef09a4433b2b0fce8f4300
This commit is contained in:
Chris Craik
parent
68a029edbb
commit
3e010f3138
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@ -39,7 +39,9 @@ public:
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Region(const Region& rhs);
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explicit Region(const Rect& rhs);
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~Region();
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static Region createTJunctionFreeRegion(const Region& r);
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Region& operator = (const Region& rhs);
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inline bool isEmpty() const { return getBounds().isEmpty(); }
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@ -47,6 +47,11 @@ enum {
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op_xor = region_operator<Rect>::op_xor
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};
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enum {
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direction_LTR,
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direction_RTL
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};
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// ----------------------------------------------------------------------------
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Region::Region() {
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@ -69,6 +74,133 @@ Region::~Region()
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{
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}
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/**
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* Copy rects from the src vector into the dst vector, resolving vertical T-Junctions along the way
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*
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* First pass through, divideSpanRTL will be set because the 'previous span' (indexing into the dst
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* vector) will be reversed. Each rectangle in the original list, starting from the bottom, will be
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* compared with the span directly below, and subdivided as needed to resolve T-junctions.
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*
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* The resulting temporary vector will be a completely reversed copy of the original, without any
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* bottom-up T-junctions.
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*
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* Second pass through, divideSpanRTL will be false since the previous span will index into the
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* final, correctly ordered region buffer. Each rectangle will be compared with the span directly
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* above it, and subdivided to resolve any remaining T-junctions.
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*/
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static void reverseRectsResolvingJunctions(const Rect* begin, const Rect* end,
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Vector<Rect>& dst, int spanDirection) {
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dst.clear();
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const Rect* current = end - 1;
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int lastTop = current->top;
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// add first span immediately
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do {
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dst.add(*current);
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current--;
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} while (current->top == lastTop && current >= begin);
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unsigned int beginLastSpan = -1;
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unsigned int endLastSpan = -1;
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int top = -1;
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int bottom = -1;
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// for all other spans, split if a t-junction exists in the span directly above
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while (current >= begin) {
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if (current->top != (current + 1)->top) {
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// new span
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if ((spanDirection == direction_RTL && current->bottom != (current + 1)->top) ||
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(spanDirection == direction_LTR && current->top != (current + 1)->bottom)) {
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// previous span not directly adjacent, don't check for T junctions
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beginLastSpan = INT_MAX;
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} else {
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beginLastSpan = endLastSpan + 1;
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}
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endLastSpan = dst.size() - 1;
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top = current->top;
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bottom = current->bottom;
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}
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int left = current->left;
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int right = current->right;
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for (unsigned int prevIndex = beginLastSpan; prevIndex <= endLastSpan; prevIndex++) {
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const Rect* prev = &dst[prevIndex];
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if (spanDirection == direction_RTL) {
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// iterating over previous span RTL, quit if it's too far left
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if (prev->right <= left) break;
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if (prev->right > left && prev->right < right) {
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dst.add(Rect(prev->right, top, right, bottom));
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right = prev->right;
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}
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if (prev->left > left && prev->left < right) {
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dst.add(Rect(prev->left, top, right, bottom));
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right = prev->left;
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}
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// if an entry in the previous span is too far right, nothing further left in the
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// current span will need it
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if (prev->left >= right) {
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beginLastSpan = prevIndex;
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}
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} else {
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// iterating over previous span LTR, quit if it's too far right
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if (prev->left >= right) break;
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if (prev->left > left && prev->left < right) {
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dst.add(Rect(left, top, prev->left, bottom));
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left = prev->left;
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}
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if (prev->right > left && prev->right < right) {
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dst.add(Rect(left, top, prev->right, bottom));
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left = prev->right;
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}
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// if an entry in the previous span is too far left, nothing further right in the
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// current span will need it
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if (prev->right <= left) {
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beginLastSpan = prevIndex;
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}
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}
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}
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if (left < right) {
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dst.add(Rect(left, top, right, bottom));
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}
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current--;
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}
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}
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/**
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* Creates a new region with the same data as the argument, but divides rectangles as necessary to
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* remove T-Junctions
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*
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* Note: the output will not necessarily be a very efficient representation of the region, since it
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* may be that a triangle-based approach would generate significantly simpler geometry
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*/
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Region Region::createTJunctionFreeRegion(const Region& r) {
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if (r.isEmpty()) return r;
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if (r.isRect()) return r;
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Vector<Rect> reversed;
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reverseRectsResolvingJunctions(r.begin(), r.end(), reversed, direction_RTL);
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Region outputRegion;
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reverseRectsResolvingJunctions(reversed.begin(), reversed.end(),
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outputRegion.mStorage, direction_LTR);
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outputRegion.mStorage.add(r.getBounds()); // to make region valid, mStorage must end with bounds
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#if VALIDATE_REGIONS
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validate(outputRegion, "T-Junction free region");
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#endif
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return outputRegion;
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}
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Region& Region::operator = (const Region& rhs)
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{
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#if VALIDATE_REGIONS
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@ -1,3 +1,27 @@
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# Build the unit tests.
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LOCAL_PATH := $(call my-dir)
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include $(CLEAR_VARS)
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# Build the unit tests.
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test_src_files := \
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Region_test.cpp
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shared_libraries := \
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libui
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static_libraries := \
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libgtest \
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libgtest_main
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$(foreach file,$(test_src_files), \
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$(eval include $(CLEAR_VARS)) \
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$(eval LOCAL_SHARED_LIBRARIES := $(shared_libraries)) \
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$(eval LOCAL_STATIC_LIBRARIES := $(static_libraries)) \
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$(eval LOCAL_SRC_FILES := $(file)) \
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$(eval LOCAL_MODULE := $(notdir $(file:%.cpp=%))) \
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$(eval include $(BUILD_NATIVE_TEST)) \
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)
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# Build the unit tests.
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LOCAL_PATH:= $(call my-dir)
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include $(CLEAR_VARS)
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@ -0,0 +1,156 @@
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "RegionTest"
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#include <stdlib.h>
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#include <ui/Region.h>
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#include <ui/Rect.h>
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#include <gtest/gtest.h>
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namespace android {
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class RegionTest : public testing::Test {
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protected:
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void checkVertTJunction(const Rect* lhs, const Rect* rhs) {
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EXPECT_FALSE((rhs->right > lhs->left && rhs->right < lhs->right) ||
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(rhs->left > lhs->left && rhs->left < lhs->right));
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}
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void verifyNoTJunctions(const Region& r) {
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for (const Rect* current = r.begin(); current < r.end(); current++) {
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for (const Rect* other = current - 1; other >= r.begin(); other--) {
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if (other->bottom < current->top) break;
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if (other->bottom != current->top) continue;
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checkVertTJunction(current, other);
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}
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for (const Rect* other = current + 1; other < r.end(); other++) {
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if (other->top > current->bottom) break;
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if (other->top != current->bottom) continue;
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checkVertTJunction(current, other);
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}
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}
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}
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void checkTJunctionFreeFromRegion(const Region& original, int expectedCount = -1) {
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Region modified = Region::createTJunctionFreeRegion(original);
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verifyNoTJunctions(modified);
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if (expectedCount != -1) {
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EXPECT_EQ(modified.end() - modified.begin(), expectedCount);
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}
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EXPECT_TRUE((original ^ modified).isEmpty());
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}
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};
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TEST_F(RegionTest, MinimalDivision_TJunction) {
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Region r;
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// | x |
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// |xxx|
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r.clear();
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r.orSelf(Rect(1, 0, 2, 1));
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r.orSelf(Rect(0, 1, 3, 2));
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checkTJunctionFreeFromRegion(r, 4);
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// | x |
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// | |
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// |xxx|
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r.clear();
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r.orSelf(Rect(1, 0, 2, 1));
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r.orSelf(Rect(0, 2, 3, 3));
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checkTJunctionFreeFromRegion(r, 2);
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}
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TEST_F(RegionTest, Trivial_TJunction) {
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Region r;
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checkTJunctionFreeFromRegion(r);
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r.orSelf(Rect(100, 100, 500, 500));
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checkTJunctionFreeFromRegion(r);
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}
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TEST_F(RegionTest, Simple_TJunction) {
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Region r;
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// | x |
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// |xxxx|
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// |xxxx|
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// |xxxx|
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r.clear();
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r.orSelf(Rect(1, 0, 2, 1));
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r.orSelf(Rect(0, 1, 3, 3));
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checkTJunctionFreeFromRegion(r);
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// | x |
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// |xx |
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// |xxx|
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r.clear();
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r.orSelf(Rect(2,0,4,2));
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r.orSelf(Rect(0,2,4,4));
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r.orSelf(Rect(0,4,6,6));
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checkTJunctionFreeFromRegion(r);
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// |x x|
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// |xxx|
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// |x x|
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r.clear();
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r.orSelf(Rect(0,0,2,6));
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r.orSelf(Rect(4,0,6,6));
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r.orSelf(Rect(0,2,6,4));
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checkTJunctionFreeFromRegion(r);
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// |xxx|
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// | x |
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// | x |
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r.clear();
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r.orSelf(Rect(0,0,6,2));
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r.orSelf(Rect(2,2,4,6));
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checkTJunctionFreeFromRegion(r);
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}
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TEST_F(RegionTest, Bigger_TJunction) {
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Region r;
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// |xxxx |
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// | xxxx |
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// | xxxx |
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// | xxxx|
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for (int i = 0; i < 4; i++) {
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r.orSelf(Rect(i,i,i+4,i+1));
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}
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checkTJunctionFreeFromRegion(r, 16);
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}
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#define ITER_MAX 1000
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#define X_MAX 8
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#define Y_MAX 8
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TEST_F(RegionTest, Random_TJunction) {
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Region r;
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srandom(12345);
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for (int iter = 0; iter < ITER_MAX; iter++) {
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r.clear();
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for (int i = 0; i < X_MAX; i++) {
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for (int j = 0; j < Y_MAX; j++) {
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if (random() % 2) {
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r.orSelf(Rect(i, j, i + 1, j + 1));
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}
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}
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}
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checkTJunctionFreeFromRegion(r);
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}
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}
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}; // namespace android
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@ -1,16 +0,0 @@
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LOCAL_PATH:= $(call my-dir)
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include $(CLEAR_VARS)
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LOCAL_SRC_FILES:= \
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region.cpp
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LOCAL_SHARED_LIBRARIES := \
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libcutils \
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libutils \
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libui
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LOCAL_MODULE:= test-region
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LOCAL_MODULE_TAGS := tests
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include $(BUILD_EXECUTABLE)
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@ -1,69 +0,0 @@
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/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "Region"
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#include <stdio.h>
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#include <utils/Debug.h>
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#include <ui/Rect.h>
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#include <ui/Region.h>
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using namespace android;
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int main()
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{
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Region empty;
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Region reg0( Rect( 0, 0, 100, 100 ) );
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Region reg1 = reg0;
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Region reg2, reg3;
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Region reg4 = empty | reg1;
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Region reg5 = reg1 | empty;
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reg4.dump("reg4");
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reg5.dump("reg5");
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reg0.dump("reg0");
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reg1.dump("reg1");
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reg0 = reg0 | reg0.translate(150, 0);
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reg0.dump("reg0");
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reg1.dump("reg1");
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reg0 = reg0 | reg0.translate(300, 0);
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reg0.dump("reg0");
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reg1.dump("reg1");
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//reg2 = reg0 | reg0.translate(0, 100);
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//reg0.dump("reg0");
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//reg1.dump("reg1");
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//reg2.dump("reg2");
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//reg3 = reg0 | reg0.translate(0, 150);
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//reg0.dump("reg0");
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//reg1.dump("reg1");
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//reg2.dump("reg2");
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//reg3.dump("reg3");
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ALOGD("---");
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reg2 = reg0 | reg0.translate(100, 0);
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reg0.dump("reg0");
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reg1.dump("reg1");
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reg2.dump("reg2");
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return 0;
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}
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