michael@0: /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "TextRenderer.h"
michael@0: #include "FontData.h"
michael@0: #include "png.h"
michael@0: #include "mozilla/Base64.h"
michael@0: #include "mozilla/layers/Compositor.h"
michael@0: #include "mozilla/layers/TextureHost.h"
michael@0: #include "mozilla/layers/Effects.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace layers {
michael@0: 
michael@0: using namespace gfx;
michael@0: using namespace std;
michael@0: 
michael@0: const Float sBackgroundOpacity = 0.6f;
michael@0: const SurfaceFormat sTextureFormat = SurfaceFormat::B8G8R8A8;
michael@0: 
michael@0: static void PNGAPI info_callback(png_structp png_ptr, png_infop info_ptr)
michael@0: {
michael@0:   png_read_update_info(png_ptr, info_ptr);
michael@0: }
michael@0: 
michael@0: static void PNGAPI row_callback(png_structp png_ptr, png_bytep new_row, png_uint_32 row_num, int pass)
michael@0: {
michael@0:   MOZ_ASSERT(sTextureFormat == SurfaceFormat::B8G8R8A8);
michael@0: 
michael@0:   DataSourceSurface::MappedSurface map = static_cast<TextRenderer*>(png_get_progressive_ptr(png_ptr))->GetSurfaceMap();
michael@0: 
michael@0:   uint32_t* dst = (uint32_t*)(map.mData + map.mStride * row_num);
michael@0: 
michael@0:   for (uint32_t x = 0; x < sTextureWidth; x++) {
michael@0:     // We blend to a transparent white background, this will make text readable
michael@0:     // even if it's on a dark background. Without hurting our ability to
michael@0:     // interact with the content behind the text.
michael@0:     Float alphaValue = Float(0xFF - new_row[x]) / 255.0f;
michael@0:     Float baseValue = sBackgroundOpacity * (1.0f - alphaValue);
michael@0:     Color pixelColor(baseValue, baseValue, baseValue, baseValue + alphaValue);
michael@0:     dst[x] = pixelColor.ToABGR();
michael@0:   }
michael@0: }
michael@0: 
michael@0: TextRenderer::~TextRenderer()
michael@0: {
michael@0:   if (mGlyphBitmaps) {
michael@0:     mGlyphBitmaps->Unmap();
michael@0:   }
michael@0: }
michael@0: 
michael@0: void
michael@0: TextRenderer::RenderText(const string& aText, const IntPoint& aOrigin,
michael@0:                          const Matrix4x4& aTransform, uint32_t aTextSize,
michael@0:                          uint32_t aTargetPixelWidth)
michael@0: {
michael@0:   EnsureInitialized();
michael@0: 
michael@0:   // For now we only have a bitmap font with a 16px cell size, so we just
michael@0:   // scale it up if the user wants larger text.
michael@0:   Float scaleFactor = Float(aTextSize) / Float(sCellHeight);
michael@0: 
michael@0:   aTargetPixelWidth /= scaleFactor;
michael@0: 
michael@0:   uint32_t numLines = 1;
michael@0:   uint32_t maxWidth = 0;
michael@0:   uint32_t lineWidth = 0;
michael@0:   // Calculate the size of the surface needed to draw all the glyphs.
michael@0:   for (uint32_t i = 0; i < aText.length(); i++) {
michael@0:     // Insert a line break if we go past the TargetPixelWidth.
michael@0:     // XXX - this has the downside of overrunning the intended width, causing
michael@0:     // things at the edge of a window to be cut off.
michael@0:     if (aText[i] == '\n' || (aText[i] == ' ' && lineWidth > aTargetPixelWidth)) {
michael@0:       numLines++;
michael@0:       lineWidth = 0;
michael@0:       continue;
michael@0:     }
michael@0: 
michael@0:     lineWidth += sGlyphWidths[uint32_t(aText[i])];
michael@0:     maxWidth = std::max(lineWidth, maxWidth);
michael@0:   }
michael@0: 
michael@0:   // Create a surface to draw our glyphs to.
michael@0:   RefPtr<DataSourceSurface> textSurf =
michael@0:     Factory::CreateDataSourceSurface(IntSize(maxWidth, numLines * sCellHeight), sTextureFormat);
michael@0: 
michael@0:   DataSourceSurface::MappedSurface map;
michael@0:   textSurf->Map(DataSourceSurface::MapType::READ_WRITE, &map);
michael@0: 
michael@0:   // Initialize the surface to transparent white.
michael@0:   memset(map.mData, uint8_t(sBackgroundOpacity * 255.0f),
michael@0:          numLines * sCellHeight * map.mStride);
michael@0: 
michael@0:   uint32_t currentXPos = 0;
michael@0:   uint32_t currentYPos = 0;
michael@0: 
michael@0:   // Copy our glyphs onto the surface.
michael@0:   for (uint32_t i = 0; i < aText.length(); i++) {
michael@0:     if (aText[i] == '\n' || (aText[i] == ' ' && currentXPos > aTargetPixelWidth)) {
michael@0:       currentYPos += sCellHeight;
michael@0:       currentXPos = 0;
michael@0:       continue;
michael@0:     }
michael@0: 
michael@0:     uint32_t glyphXOffset = aText[i] % (sTextureWidth / sCellWidth) * sCellWidth * BytesPerPixel(sTextureFormat);
michael@0:     uint32_t truncatedLine = aText[i] / (sTextureWidth / sCellWidth);
michael@0:     uint32_t glyphYOffset =  truncatedLine * sCellHeight * mMap.mStride;
michael@0: 
michael@0:     for (int y = 0; y < 16; y++) {
michael@0:       memcpy(map.mData + (y + currentYPos) * map.mStride + currentXPos * BytesPerPixel(sTextureFormat),
michael@0:              mMap.mData + glyphYOffset + y * mMap.mStride + glyphXOffset,
michael@0:              sGlyphWidths[uint32_t(aText[i])] * BytesPerPixel(sTextureFormat));
michael@0:     }
michael@0: 
michael@0:     currentXPos += sGlyphWidths[uint32_t(aText[i])];
michael@0:   }
michael@0: 
michael@0:   textSurf->Unmap();
michael@0: 
michael@0:   RefPtr<DataTextureSource> src = mCompositor->CreateDataTextureSource();
michael@0: 
michael@0:   if (!src->Update(textSurf)) {
michael@0:     // Upload failed.
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   RefPtr<EffectRGB> effect = new EffectRGB(src, true, Filter::LINEAR);
michael@0:   EffectChain chain;
michael@0:   chain.mPrimaryEffect = effect;
michael@0: 
michael@0:   Matrix4x4 transform = aTransform;
michael@0:   transform.Scale(scaleFactor, scaleFactor, 1.0f);
michael@0:   mCompositor->DrawQuad(Rect(aOrigin.x, aOrigin.y, maxWidth, numLines * 16),
michael@0:                         Rect(-10000, -10000, 20000, 20000), chain, 1.0f, transform);
michael@0: }
michael@0: 
michael@0: void
michael@0: TextRenderer::EnsureInitialized()
michael@0: {
michael@0:   if (mGlyphBitmaps) {
michael@0:     return;
michael@0:   }
michael@0: 
michael@0:   mGlyphBitmaps = Factory::CreateDataSourceSurface(IntSize(sTextureWidth, sTextureHeight), sTextureFormat);
michael@0: 
michael@0:   mGlyphBitmaps->Map(DataSourceSurface::MapType::READ_WRITE, &mMap);
michael@0: 
michael@0:   png_structp png_ptr = NULL;
michael@0:   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
michael@0: 
michael@0:   png_set_progressive_read_fn(png_ptr, this, info_callback, row_callback, nullptr);
michael@0:   png_infop info_ptr = NULL;
michael@0:   info_ptr = png_create_info_struct(png_ptr);
michael@0: 
michael@0:   png_process_data(png_ptr, info_ptr, (uint8_t*)sFontPNG, sizeof(sFontPNG));
michael@0: 
michael@0:   png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
michael@0: }
michael@0: 
michael@0: }
michael@0: }