1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/layers/composite/TextRenderer.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,163 @@
1.4 +/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "TextRenderer.h"
1.10 +#include "FontData.h"
1.11 +#include "png.h"
1.12 +#include "mozilla/Base64.h"
1.13 +#include "mozilla/layers/Compositor.h"
1.14 +#include "mozilla/layers/TextureHost.h"
1.15 +#include "mozilla/layers/Effects.h"
1.16 +
1.17 +namespace mozilla {
1.18 +namespace layers {
1.19 +
1.20 +using namespace gfx;
1.21 +using namespace std;
1.22 +
1.23 +const Float sBackgroundOpacity = 0.6f;
1.24 +const SurfaceFormat sTextureFormat = SurfaceFormat::B8G8R8A8;
1.25 +
1.26 +static void PNGAPI info_callback(png_structp png_ptr, png_infop info_ptr)
1.27 +{
1.28 + png_read_update_info(png_ptr, info_ptr);
1.29 +}
1.30 +
1.31 +static void PNGAPI row_callback(png_structp png_ptr, png_bytep new_row, png_uint_32 row_num, int pass)
1.32 +{
1.33 + MOZ_ASSERT(sTextureFormat == SurfaceFormat::B8G8R8A8);
1.34 +
1.35 + DataSourceSurface::MappedSurface map = static_cast<TextRenderer*>(png_get_progressive_ptr(png_ptr))->GetSurfaceMap();
1.36 +
1.37 + uint32_t* dst = (uint32_t*)(map.mData + map.mStride * row_num);
1.38 +
1.39 + for (uint32_t x = 0; x < sTextureWidth; x++) {
1.40 + // We blend to a transparent white background, this will make text readable
1.41 + // even if it's on a dark background. Without hurting our ability to
1.42 + // interact with the content behind the text.
1.43 + Float alphaValue = Float(0xFF - new_row[x]) / 255.0f;
1.44 + Float baseValue = sBackgroundOpacity * (1.0f - alphaValue);
1.45 + Color pixelColor(baseValue, baseValue, baseValue, baseValue + alphaValue);
1.46 + dst[x] = pixelColor.ToABGR();
1.47 + }
1.48 +}
1.49 +
1.50 +TextRenderer::~TextRenderer()
1.51 +{
1.52 + if (mGlyphBitmaps) {
1.53 + mGlyphBitmaps->Unmap();
1.54 + }
1.55 +}
1.56 +
1.57 +void
1.58 +TextRenderer::RenderText(const string& aText, const IntPoint& aOrigin,
1.59 + const Matrix4x4& aTransform, uint32_t aTextSize,
1.60 + uint32_t aTargetPixelWidth)
1.61 +{
1.62 + EnsureInitialized();
1.63 +
1.64 + // For now we only have a bitmap font with a 16px cell size, so we just
1.65 + // scale it up if the user wants larger text.
1.66 + Float scaleFactor = Float(aTextSize) / Float(sCellHeight);
1.67 +
1.68 + aTargetPixelWidth /= scaleFactor;
1.69 +
1.70 + uint32_t numLines = 1;
1.71 + uint32_t maxWidth = 0;
1.72 + uint32_t lineWidth = 0;
1.73 + // Calculate the size of the surface needed to draw all the glyphs.
1.74 + for (uint32_t i = 0; i < aText.length(); i++) {
1.75 + // Insert a line break if we go past the TargetPixelWidth.
1.76 + // XXX - this has the downside of overrunning the intended width, causing
1.77 + // things at the edge of a window to be cut off.
1.78 + if (aText[i] == '\n' || (aText[i] == ' ' && lineWidth > aTargetPixelWidth)) {
1.79 + numLines++;
1.80 + lineWidth = 0;
1.81 + continue;
1.82 + }
1.83 +
1.84 + lineWidth += sGlyphWidths[uint32_t(aText[i])];
1.85 + maxWidth = std::max(lineWidth, maxWidth);
1.86 + }
1.87 +
1.88 + // Create a surface to draw our glyphs to.
1.89 + RefPtr<DataSourceSurface> textSurf =
1.90 + Factory::CreateDataSourceSurface(IntSize(maxWidth, numLines * sCellHeight), sTextureFormat);
1.91 +
1.92 + DataSourceSurface::MappedSurface map;
1.93 + textSurf->Map(DataSourceSurface::MapType::READ_WRITE, &map);
1.94 +
1.95 + // Initialize the surface to transparent white.
1.96 + memset(map.mData, uint8_t(sBackgroundOpacity * 255.0f),
1.97 + numLines * sCellHeight * map.mStride);
1.98 +
1.99 + uint32_t currentXPos = 0;
1.100 + uint32_t currentYPos = 0;
1.101 +
1.102 + // Copy our glyphs onto the surface.
1.103 + for (uint32_t i = 0; i < aText.length(); i++) {
1.104 + if (aText[i] == '\n' || (aText[i] == ' ' && currentXPos > aTargetPixelWidth)) {
1.105 + currentYPos += sCellHeight;
1.106 + currentXPos = 0;
1.107 + continue;
1.108 + }
1.109 +
1.110 + uint32_t glyphXOffset = aText[i] % (sTextureWidth / sCellWidth) * sCellWidth * BytesPerPixel(sTextureFormat);
1.111 + uint32_t truncatedLine = aText[i] / (sTextureWidth / sCellWidth);
1.112 + uint32_t glyphYOffset = truncatedLine * sCellHeight * mMap.mStride;
1.113 +
1.114 + for (int y = 0; y < 16; y++) {
1.115 + memcpy(map.mData + (y + currentYPos) * map.mStride + currentXPos * BytesPerPixel(sTextureFormat),
1.116 + mMap.mData + glyphYOffset + y * mMap.mStride + glyphXOffset,
1.117 + sGlyphWidths[uint32_t(aText[i])] * BytesPerPixel(sTextureFormat));
1.118 + }
1.119 +
1.120 + currentXPos += sGlyphWidths[uint32_t(aText[i])];
1.121 + }
1.122 +
1.123 + textSurf->Unmap();
1.124 +
1.125 + RefPtr<DataTextureSource> src = mCompositor->CreateDataTextureSource();
1.126 +
1.127 + if (!src->Update(textSurf)) {
1.128 + // Upload failed.
1.129 + return;
1.130 + }
1.131 +
1.132 + RefPtr<EffectRGB> effect = new EffectRGB(src, true, Filter::LINEAR);
1.133 + EffectChain chain;
1.134 + chain.mPrimaryEffect = effect;
1.135 +
1.136 + Matrix4x4 transform = aTransform;
1.137 + transform.Scale(scaleFactor, scaleFactor, 1.0f);
1.138 + mCompositor->DrawQuad(Rect(aOrigin.x, aOrigin.y, maxWidth, numLines * 16),
1.139 + Rect(-10000, -10000, 20000, 20000), chain, 1.0f, transform);
1.140 +}
1.141 +
1.142 +void
1.143 +TextRenderer::EnsureInitialized()
1.144 +{
1.145 + if (mGlyphBitmaps) {
1.146 + return;
1.147 + }
1.148 +
1.149 + mGlyphBitmaps = Factory::CreateDataSourceSurface(IntSize(sTextureWidth, sTextureHeight), sTextureFormat);
1.150 +
1.151 + mGlyphBitmaps->Map(DataSourceSurface::MapType::READ_WRITE, &mMap);
1.152 +
1.153 + png_structp png_ptr = NULL;
1.154 + png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
1.155 +
1.156 + png_set_progressive_read_fn(png_ptr, this, info_callback, row_callback, nullptr);
1.157 + png_infop info_ptr = NULL;
1.158 + info_ptr = png_create_info_struct(png_ptr);
1.159 +
1.160 + png_process_data(png_ptr, info_ptr, (uint8_t*)sFontPNG, sizeof(sFontPNG));
1.161 +
1.162 + png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
1.163 +}
1.164 +
1.165 +}
1.166 +}
