| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #define LOG_TAG "OpenGLRenderer" |
| |
| #include <SkUtils.h> |
| |
| #include <cutils/properties.h> |
| #include <utils/Log.h> |
| |
| #include "FontRenderer.h" |
| |
| namespace android { |
| namespace uirenderer { |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Defines |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #define DEFAULT_TEXT_CACHE_WIDTH 1024 |
| #define DEFAULT_TEXT_CACHE_HEIGHT 256 |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Font |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| Font::Font(FontRenderer* state, uint32_t fontId, float fontSize) : |
| mState(state), mFontId(fontId), mFontSize(fontSize) { |
| } |
| |
| |
| Font::~Font() { |
| for (uint32_t ct = 0; ct < mState->mActiveFonts.size(); ct++) { |
| if (mState->mActiveFonts[ct] == this) { |
| mState->mActiveFonts.removeAt(ct); |
| break; |
| } |
| } |
| |
| for (uint32_t i = 0; i < mCachedGlyphs.size(); i++) { |
| CachedGlyphInfo* glyph = mCachedGlyphs.valueAt(i); |
| delete glyph; |
| } |
| } |
| |
| void Font::invalidateTextureCache() { |
| for (uint32_t i = 0; i < mCachedGlyphs.size(); i++) { |
| mCachedGlyphs.valueAt(i)->mIsValid = false; |
| } |
| } |
| |
| void Font::drawCachedGlyph(CachedGlyphInfo* glyph, int x, int y) { |
| int nPenX = x + glyph->mBitmapLeft; |
| int nPenY = y + glyph->mBitmapTop + glyph->mBitmapHeight; |
| |
| float u1 = glyph->mBitmapMinU; |
| float u2 = glyph->mBitmapMaxU; |
| float v1 = glyph->mBitmapMinV; |
| float v2 = glyph->mBitmapMaxV; |
| |
| int width = (int) glyph->mBitmapWidth; |
| int height = (int) glyph->mBitmapHeight; |
| |
| mState->appendMeshQuad(nPenX, nPenY, 0, u1, v2, |
| nPenX + width, nPenY, 0, u2, v2, |
| nPenX + width, nPenY - height, 0, u2, v1, |
| nPenX, nPenY - height, 0, u1, v1); |
| } |
| |
| void Font::drawCachedGlyph(CachedGlyphInfo *glyph, int x, int y, |
| uint8_t *bitmap, uint32_t bitmapW, uint32_t bitmapH) { |
| int nPenX = x + glyph->mBitmapLeft; |
| int nPenY = y + glyph->mBitmapTop; |
| |
| uint32_t endX = glyph->mStartX + glyph->mBitmapWidth; |
| uint32_t endY = glyph->mStartY + glyph->mBitmapHeight; |
| |
| if(nPenX < 0 || nPenY < 0) { |
| LOGE("Cannot render into a bitmap, some of the glyph is below zero"); |
| return; |
| } |
| |
| if(nPenX + glyph->mBitmapWidth >= bitmapW || nPenY + glyph->mBitmapHeight >= bitmapH) { |
| LOGE("Cannot render into a bitmap, dimentions too small"); |
| return; |
| } |
| |
| uint32_t cacheWidth = mState->getCacheWidth(); |
| const uint8_t* cacheBuffer = mState->getTextTextureData(); |
| |
| uint32_t cacheX = 0, bX = 0, cacheY = 0, bY = 0; |
| for (cacheX = glyph->mStartX, bX = nPenX; cacheX < endX; cacheX++, bX++) { |
| for (cacheY = glyph->mStartY, bY = nPenY; cacheY < endY; cacheY++, bY++) { |
| uint8_t tempCol = cacheBuffer[cacheY * cacheWidth + cacheX]; |
| bitmap[bY * bitmapW + bX] = tempCol; |
| } |
| } |
| |
| } |
| |
| Font::CachedGlyphInfo* Font::getCachedUTFChar(SkPaint* paint, int32_t utfChar) { |
| CachedGlyphInfo* cachedGlyph = mCachedGlyphs.valueFor(utfChar); |
| if (cachedGlyph == NULL) { |
| cachedGlyph = cacheGlyph(paint, utfChar); |
| } |
| |
| // Is the glyph still in texture cache? |
| if (!cachedGlyph->mIsValid) { |
| const SkGlyph& skiaGlyph = paint->getUnicharMetrics(utfChar); |
| updateGlyphCache(paint, skiaGlyph, cachedGlyph); |
| } |
| |
| return cachedGlyph; |
| } |
| |
| void Font::renderUTF(SkPaint* paint, const char* text, uint32_t start, uint32_t len, |
| int numGlyphs, int x, int y, uint8_t *bitmap, uint32_t bitmapW, uint32_t bitmapH) { |
| if (numGlyphs == 0 || text == NULL || len == 0) { |
| return; |
| } |
| |
| int penX = x, penY = y; |
| int glyphsLeft = 1; |
| if (numGlyphs > 0) { |
| glyphsLeft = numGlyphs; |
| } |
| |
| text += start; |
| |
| while (glyphsLeft > 0) { |
| int32_t utfChar = SkUTF16_NextUnichar((const uint16_t**) &text); |
| |
| // Reached the end of the string or encountered |
| if (utfChar < 0) { |
| break; |
| } |
| |
| CachedGlyphInfo* cachedGlyph = getCachedUTFChar(paint, utfChar); |
| |
| // If it's still not valid, we couldn't cache it, so we shouldn't draw garbage |
| if (cachedGlyph->mIsValid) { |
| if(bitmap != NULL) { |
| drawCachedGlyph(cachedGlyph, penX, penY, bitmap, bitmapW, bitmapH); |
| } |
| else { |
| drawCachedGlyph(cachedGlyph, penX, penY); |
| } |
| } |
| |
| penX += SkFixedFloor(cachedGlyph->mAdvanceX); |
| |
| // If we were given a specific number of glyphs, decrement |
| if (numGlyphs > 0) { |
| glyphsLeft--; |
| } |
| } |
| } |
| |
| void Font::updateGlyphCache(SkPaint* paint, const SkGlyph& skiaGlyph, CachedGlyphInfo* glyph) { |
| glyph->mAdvanceX = skiaGlyph.fAdvanceX; |
| glyph->mAdvanceY = skiaGlyph.fAdvanceY; |
| glyph->mBitmapLeft = skiaGlyph.fLeft; |
| glyph->mBitmapTop = skiaGlyph.fTop; |
| |
| uint32_t startX = 0; |
| uint32_t startY = 0; |
| |
| // Get the bitmap for the glyph |
| paint->findImage(skiaGlyph); |
| glyph->mIsValid = mState->cacheBitmap(skiaGlyph, &startX, &startY); |
| |
| if (!glyph->mIsValid) { |
| return; |
| } |
| |
| uint32_t endX = startX + skiaGlyph.fWidth; |
| uint32_t endY = startY + skiaGlyph.fHeight; |
| |
| glyph->mStartX = startX; |
| glyph->mStartY = startY; |
| glyph->mBitmapWidth = skiaGlyph.fWidth; |
| glyph->mBitmapHeight = skiaGlyph.fHeight; |
| |
| uint32_t cacheWidth = mState->getCacheWidth(); |
| uint32_t cacheHeight = mState->getCacheHeight(); |
| |
| glyph->mBitmapMinU = (float) startX / (float) cacheWidth; |
| glyph->mBitmapMinV = (float) startY / (float) cacheHeight; |
| glyph->mBitmapMaxU = (float) endX / (float) cacheWidth; |
| glyph->mBitmapMaxV = (float) endY / (float) cacheHeight; |
| |
| mState->mUploadTexture = true; |
| } |
| |
| Font::CachedGlyphInfo* Font::cacheGlyph(SkPaint* paint, int32_t glyph) { |
| CachedGlyphInfo* newGlyph = new CachedGlyphInfo(); |
| mCachedGlyphs.add(glyph, newGlyph); |
| |
| const SkGlyph& skiaGlyph = paint->getUnicharMetrics(glyph); |
| newGlyph->mGlyphIndex = skiaGlyph.fID; |
| newGlyph->mIsValid = false; |
| |
| updateGlyphCache(paint, skiaGlyph, newGlyph); |
| |
| return newGlyph; |
| } |
| |
| Font* Font::create(FontRenderer* state, uint32_t fontId, float fontSize) { |
| Vector<Font*> &activeFonts = state->mActiveFonts; |
| |
| for (uint32_t i = 0; i < activeFonts.size(); i++) { |
| Font* font = activeFonts[i]; |
| if (font->mFontId == fontId && font->mFontSize == fontSize) { |
| return font; |
| } |
| } |
| |
| Font* newFont = new Font(state, fontId, fontSize); |
| activeFonts.push(newFont); |
| return newFont; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // FontRenderer |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| FontRenderer::FontRenderer() { |
| LOGD("Creating FontRenderer"); |
| |
| mInitialized = false; |
| mMaxNumberOfQuads = 1024; |
| mCurrentQuadIndex = 0; |
| mTextureId = 0; |
| |
| mIndexBufferID = 0; |
| |
| mCacheWidth = DEFAULT_TEXT_CACHE_WIDTH; |
| mCacheHeight = DEFAULT_TEXT_CACHE_HEIGHT; |
| |
| char property[PROPERTY_VALUE_MAX]; |
| if (property_get(PROPERTY_TEXT_CACHE_WIDTH, property, NULL) > 0) { |
| LOGD(" Setting text cache width to %s pixels", property); |
| mCacheWidth = atoi(property); |
| } else { |
| LOGD(" Using default text cache width of %i pixels", mCacheWidth); |
| } |
| |
| if (property_get(PROPERTY_TEXT_CACHE_HEIGHT, property, NULL) > 0) { |
| LOGD(" Setting text cache width to %s pixels", property); |
| mCacheHeight = atoi(property); |
| } else { |
| LOGD(" Using default text cache height of %i pixels", mCacheHeight); |
| } |
| } |
| |
| FontRenderer::~FontRenderer() { |
| for (uint32_t i = 0; i < mCacheLines.size(); i++) { |
| delete mCacheLines[i]; |
| } |
| mCacheLines.clear(); |
| |
| delete[] mTextMeshPtr; |
| delete[] mTextTexture; |
| |
| if(mTextureId) { |
| glDeleteTextures(1, &mTextureId); |
| } |
| |
| Vector<Font*> fontsToDereference = mActiveFonts; |
| for (uint32_t i = 0; i < fontsToDereference.size(); i++) { |
| delete fontsToDereference[i]; |
| } |
| } |
| |
| void FontRenderer::flushAllAndInvalidate() { |
| if (mCurrentQuadIndex != 0) { |
| issueDrawCommand(); |
| mCurrentQuadIndex = 0; |
| } |
| for (uint32_t i = 0; i < mActiveFonts.size(); i++) { |
| mActiveFonts[i]->invalidateTextureCache(); |
| } |
| for (uint32_t i = 0; i < mCacheLines.size(); i++) { |
| mCacheLines[i]->mCurrentCol = 0; |
| } |
| } |
| |
| bool FontRenderer::cacheBitmap(const SkGlyph& glyph, uint32_t* retOriginX, uint32_t* retOriginY) { |
| // If the glyph is too tall, don't cache it |
| if (glyph.fWidth > mCacheLines[mCacheLines.size() - 1]->mMaxHeight) { |
| LOGE("Font size to large to fit in cache. width, height = %i, %i", |
| (int) glyph.fWidth, (int) glyph.fHeight); |
| return false; |
| } |
| |
| // Now copy the bitmap into the cache texture |
| uint32_t startX = 0; |
| uint32_t startY = 0; |
| |
| bool bitmapFit = false; |
| for (uint32_t i = 0; i < mCacheLines.size(); i++) { |
| bitmapFit = mCacheLines[i]->fitBitmap(glyph, &startX, &startY); |
| if (bitmapFit) { |
| break; |
| } |
| } |
| |
| // If the new glyph didn't fit, flush the state so far and invalidate everything |
| if (!bitmapFit) { |
| flushAllAndInvalidate(); |
| |
| // Try to fit it again |
| for (uint32_t i = 0; i < mCacheLines.size(); i++) { |
| bitmapFit = mCacheLines[i]->fitBitmap(glyph, &startX, &startY); |
| if (bitmapFit) { |
| break; |
| } |
| } |
| |
| // if we still don't fit, something is wrong and we shouldn't draw |
| if (!bitmapFit) { |
| LOGE("Bitmap doesn't fit in cache. width, height = %i, %i", |
| (int) glyph.fWidth, (int) glyph.fHeight); |
| return false; |
| } |
| } |
| |
| *retOriginX = startX; |
| *retOriginY = startY; |
| |
| uint32_t endX = startX + glyph.fWidth; |
| uint32_t endY = startY + glyph.fHeight; |
| |
| uint32_t cacheWidth = mCacheWidth; |
| |
| uint8_t* cacheBuffer = mTextTexture; |
| uint8_t* bitmapBuffer = (uint8_t*) glyph.fImage; |
| unsigned int stride = glyph.rowBytes(); |
| |
| uint32_t cacheX = 0, bX = 0, cacheY = 0, bY = 0; |
| for (cacheX = startX, bX = 0; cacheX < endX; cacheX++, bX++) { |
| for (cacheY = startY, bY = 0; cacheY < endY; cacheY++, bY++) { |
| uint8_t tempCol = bitmapBuffer[bY * stride + bX]; |
| cacheBuffer[cacheY * cacheWidth + cacheX] = tempCol; |
| } |
| } |
| |
| return true; |
| } |
| |
| void FontRenderer::initTextTexture() { |
| mTextTexture = new uint8_t[mCacheWidth * mCacheHeight]; |
| mUploadTexture = false; |
| |
| glGenTextures(1, &mTextureId); |
| glBindTexture(GL_TEXTURE_2D, mTextureId); |
| glPixelStorei(GL_UNPACK_ALIGNMENT, 1); |
| // Initialize texture dimentions |
| glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, mCacheWidth, mCacheHeight, 0, |
| GL_ALPHA, GL_UNSIGNED_BYTE, 0); |
| |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); |
| |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); |
| |
| // Split up our cache texture into lines of certain widths |
| int nextLine = 0; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 16, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 24, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 24, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 32, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 32, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, 40, nextLine, 0)); |
| nextLine += mCacheLines.top()->mMaxHeight; |
| mCacheLines.push(new CacheTextureLine(mCacheWidth, mCacheHeight - nextLine, nextLine, 0)); |
| } |
| |
| // Avoid having to reallocate memory and render quad by quad |
| void FontRenderer::initVertexArrayBuffers() { |
| uint32_t numIndicies = mMaxNumberOfQuads * 6; |
| uint32_t indexBufferSizeBytes = numIndicies * sizeof(uint16_t); |
| uint16_t* indexBufferData = (uint16_t*) malloc(indexBufferSizeBytes); |
| |
| // Four verts, two triangles , six indices per quad |
| for (uint32_t i = 0; i < mMaxNumberOfQuads; i++) { |
| int i6 = i * 6; |
| int i4 = i * 4; |
| |
| indexBufferData[i6 + 0] = i4 + 0; |
| indexBufferData[i6 + 1] = i4 + 1; |
| indexBufferData[i6 + 2] = i4 + 2; |
| |
| indexBufferData[i6 + 3] = i4 + 0; |
| indexBufferData[i6 + 4] = i4 + 2; |
| indexBufferData[i6 + 5] = i4 + 3; |
| } |
| |
| glGenBuffers(1, &mIndexBufferID); |
| glBindBuffer(GL_ARRAY_BUFFER, mIndexBufferID); |
| glBufferData(GL_ARRAY_BUFFER, indexBufferSizeBytes, indexBufferData, GL_DYNAMIC_DRAW); |
| glBindBuffer(GL_ARRAY_BUFFER, 0); |
| |
| free(indexBufferData); |
| |
| uint32_t coordSize = 3; |
| uint32_t uvSize = 2; |
| uint32_t vertsPerQuad = 4; |
| uint32_t vertexBufferSize = mMaxNumberOfQuads * vertsPerQuad * coordSize * uvSize; |
| mTextMeshPtr = new float[vertexBufferSize]; |
| } |
| |
| // We don't want to allocate anything unless we actually draw text |
| void FontRenderer::checkInit() { |
| if (mInitialized) { |
| return; |
| } |
| |
| initTextTexture(); |
| initVertexArrayBuffers(); |
| |
| // We store a string with letters in a rough frequency of occurrence |
| mLatinPrecache = String16("eisarntolcdugpmhbyfvkwzxjq "); |
| mLatinPrecache += String16("EISARNTOLCDUGPMHBYFVKWZXJQ"); |
| mLatinPrecache += String16(",.?!()-+@;:`'"); |
| mLatinPrecache += String16("0123456789"); |
| |
| mInitialized = true; |
| } |
| |
| void FontRenderer::checkTextureUpdate() { |
| if (!mUploadTexture) { |
| return; |
| } |
| |
| glBindTexture(GL_TEXTURE_2D, mTextureId); |
| |
| // Iterate over all the cache lines and see which ones need to be updated |
| for (uint32_t i = 0; i < mCacheLines.size(); i++) { |
| CacheTextureLine* cl = mCacheLines[i]; |
| if(cl->mDirty) { |
| uint32_t xOffset = 0; |
| uint32_t yOffset = cl->mCurrentRow; |
| uint32_t width = mCacheWidth; |
| uint32_t height = cl->mMaxHeight; |
| void* textureData = mTextTexture + yOffset*width; |
| |
| glTexSubImage2D(GL_TEXTURE_2D, 0, xOffset, yOffset, width, height, |
| GL_ALPHA, GL_UNSIGNED_BYTE, textureData); |
| |
| cl->mDirty = false; |
| } |
| } |
| |
| mUploadTexture = false; |
| } |
| |
| void FontRenderer::issueDrawCommand() { |
| |
| checkTextureUpdate(); |
| |
| float* vtx = mTextMeshPtr; |
| float* tex = vtx + 3; |
| |
| // position is slot 0 |
| uint32_t slot = 0; |
| glVertexAttribPointer(slot, 3, GL_FLOAT, false, 20, vtx); |
| |
| // texture0 is slot 1 |
| slot = 1; |
| glVertexAttribPointer(slot, 2, GL_FLOAT, false, 20, tex); |
| |
| glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mIndexBufferID); |
| glDrawElements(GL_TRIANGLES, mCurrentQuadIndex * 6, GL_UNSIGNED_SHORT, NULL); |
| } |
| |
| void FontRenderer::appendMeshQuad(float x1, float y1, float z1, float u1, float v1, float x2, |
| float y2, float z2, float u2, float v2, float x3, float y3, float z3, float u3, float v3, |
| float x4, float y4, float z4, float u4, float v4) { |
| if (x1 > mClip->right || y1 < mClip->top || x2 < mClip->left || y4 > mClip->bottom) { |
| return; |
| } |
| |
| const uint32_t vertsPerQuad = 4; |
| const uint32_t floatsPerVert = 5; |
| float* currentPos = mTextMeshPtr + mCurrentQuadIndex * vertsPerQuad * floatsPerVert; |
| |
| (*currentPos++) = x1; |
| (*currentPos++) = y1; |
| (*currentPos++) = z1; |
| (*currentPos++) = u1; |
| (*currentPos++) = v1; |
| |
| (*currentPos++) = x2; |
| (*currentPos++) = y2; |
| (*currentPos++) = z2; |
| (*currentPos++) = u2; |
| (*currentPos++) = v2; |
| |
| (*currentPos++) = x3; |
| (*currentPos++) = y3; |
| (*currentPos++) = z3; |
| (*currentPos++) = u3; |
| (*currentPos++) = v3; |
| |
| (*currentPos++) = x4; |
| (*currentPos++) = y4; |
| (*currentPos++) = z4; |
| (*currentPos++) = u4; |
| (*currentPos++) = v4; |
| |
| mCurrentQuadIndex++; |
| |
| if (mCurrentQuadIndex == mMaxNumberOfQuads) { |
| issueDrawCommand(); |
| mCurrentQuadIndex = 0; |
| } |
| } |
| |
| uint32_t FontRenderer::getRemainingCacheCapacity() { |
| uint32_t remainingCapacity = 0; |
| float totalPixels = 0; |
| for(uint32_t i = 0; i < mCacheLines.size(); i ++) { |
| remainingCapacity += (mCacheLines[i]->mMaxWidth - mCacheLines[i]->mCurrentCol); |
| totalPixels += mCacheLines[i]->mMaxWidth; |
| } |
| remainingCapacity = (remainingCapacity * 100) / totalPixels; |
| return remainingCapacity; |
| } |
| |
| void FontRenderer::precacheLatin(SkPaint* paint) { |
| // Remaining capacity is measured in % |
| uint32_t remainingCapacity = getRemainingCacheCapacity(); |
| uint32_t precacheIdx = 0; |
| while(remainingCapacity > 25 && precacheIdx < mLatinPrecache.size()) { |
| mCurrentFont->getCachedUTFChar(paint, (int32_t)mLatinPrecache[precacheIdx]); |
| remainingCapacity = getRemainingCacheCapacity(); |
| precacheIdx ++; |
| } |
| } |
| |
| void FontRenderer::setFont(SkPaint* paint, uint32_t fontId, float fontSize) { |
| uint32_t currentNumFonts = mActiveFonts.size(); |
| mCurrentFont = Font::create(this, fontId, fontSize); |
| |
| const float maxPrecacheFontSize = 40.0f; |
| bool isNewFont = currentNumFonts != mActiveFonts.size(); |
| |
| if(isNewFont && fontSize <= maxPrecacheFontSize ){ |
| precacheLatin(paint); |
| } |
| } |
| |
| void FontRenderer::renderText(SkPaint* paint, const Rect* clip, const char *text, |
| uint32_t startIndex, uint32_t len, int numGlyphs, int x, int y) { |
| checkInit(); |
| |
| if (!mCurrentFont) { |
| LOGE("No font set"); |
| return; |
| } |
| |
| mClip = clip; |
| mCurrentFont->renderUTF(paint, text, startIndex, len, numGlyphs, x, y); |
| |
| if (mCurrentQuadIndex != 0) { |
| issueDrawCommand(); |
| mCurrentQuadIndex = 0; |
| } |
| } |
| |
| void FontRenderer::computeGaussianWeights(float* weights, int32_t radius) { |
| // Compute gaussian weights for the blur |
| // e is the euler's number |
| float e = 2.718281828459045f; |
| float pi = 3.1415926535897932f; |
| // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 ) |
| // x is of the form [-radius .. 0 .. radius] |
| // and sigma varies with radius. |
| // Based on some experimental radius values and sigma's |
| // we approximately fit sigma = f(radius) as |
| // sigma = radius * 0.4 + 0.6 |
| // The larger the radius gets, the more our gaussian blur |
| // will resemble a box blur since with large sigma |
| // the gaussian curve begins to lose its shape |
| float sigma = 0.4f * (float)radius + 0.6f; |
| |
| // Now compute the coefficints |
| // We will store some redundant values to save some math during |
| // the blur calculations |
| // precompute some values |
| float coeff1 = 1.0f / (sqrt( 2.0f * pi ) * sigma); |
| float coeff2 = - 1.0f / (2.0f * sigma * sigma); |
| |
| float normalizeFactor = 0.0f; |
| for(int32_t r = -radius; r <= radius; r ++) { |
| float floatR = (float)r; |
| weights[r + radius] = coeff1 * pow(e, floatR * floatR * coeff2); |
| normalizeFactor += weights[r + radius]; |
| } |
| |
| //Now we need to normalize the weights because all our coefficients need to add up to one |
| normalizeFactor = 1.0f / normalizeFactor; |
| for(int32_t r = -radius; r <= radius; r ++) { |
| weights[r + radius] *= normalizeFactor; |
| } |
| } |
| |
| void FontRenderer::horizontalBlur(float* weights, int32_t radius, |
| const uint8_t* source, uint8_t* dest, |
| int32_t width, int32_t height) { |
| float blurredPixel = 0.0f; |
| float currentPixel = 0.0f; |
| |
| for(int32_t y = 0; y < height; y ++) { |
| |
| const uint8_t* input = source + y * width; |
| uint8_t* output = dest + y * width; |
| |
| for(int32_t x = 0; x < width; x ++) { |
| blurredPixel = 0.0f; |
| const float* gPtr = weights; |
| // Optimization for non-border pixels |
| if ((x > radius) && (x < (width - radius))) { |
| const uint8_t *i = input + (x - radius); |
| for(int r = -radius; r <= radius; r ++) { |
| currentPixel = (float)(*i); |
| blurredPixel += currentPixel * gPtr[0]; |
| gPtr++; |
| i++; |
| } |
| } else { |
| for(int32_t r = -radius; r <= radius; r ++) { |
| // Stepping left and right away from the pixel |
| int validW = x + r; |
| if(validW < 0) { |
| validW = 0; |
| } |
| if(validW > width - 1) { |
| validW = width - 1; |
| } |
| |
| currentPixel = (float)(input[validW]); |
| blurredPixel += currentPixel * gPtr[0]; |
| gPtr++; |
| } |
| } |
| *output = (uint8_t)blurredPixel; |
| output ++; |
| } |
| } |
| } |
| |
| void FontRenderer::verticalBlur(float* weights, int32_t radius, |
| const uint8_t* source, uint8_t* dest, |
| int32_t width, int32_t height) { |
| float blurredPixel = 0.0f; |
| float currentPixel = 0.0f; |
| |
| for(int32_t y = 0; y < height; y ++) { |
| |
| uint8_t* output = dest + y * width; |
| |
| for(int32_t x = 0; x < width; x ++) { |
| blurredPixel = 0.0f; |
| const float* gPtr = weights; |
| const uint8_t* input = source + x; |
| // Optimization for non-border pixels |
| if ((y > radius) && (y < (height - radius))) { |
| const uint8_t *i = input + ((y - radius) * width); |
| for(int32_t r = -radius; r <= radius; r ++) { |
| currentPixel = (float)(*i); |
| blurredPixel += currentPixel * gPtr[0]; |
| gPtr++; |
| i += width; |
| } |
| } else { |
| for(int32_t r = -radius; r <= radius; r ++) { |
| int validH = y + r; |
| // Clamp to zero and width |
| if(validH < 0) { |
| validH = 0; |
| } |
| if(validH > height - 1) { |
| validH = height - 1; |
| } |
| |
| const uint8_t *i = input + validH * width; |
| currentPixel = (float)(*i); |
| blurredPixel += currentPixel * gPtr[0]; |
| gPtr++; |
| } |
| } |
| *output = (uint8_t)blurredPixel; |
| output ++; |
| } |
| } |
| } |
| |
| |
| void FontRenderer::blurImage(uint8_t *image, int32_t width, int32_t height, int32_t radius) { |
| float *gaussian = new float[2 * radius + 1]; |
| computeGaussianWeights(gaussian, radius); |
| uint8_t* scratch = new uint8_t[width * height]; |
| horizontalBlur(gaussian, radius, image, scratch, width, height); |
| verticalBlur(gaussian, radius, scratch, image, width, height); |
| delete[] gaussian; |
| delete[] scratch; |
| } |
| |
| }; // namespace uirenderer |
| }; // namespace android |