impeller/entity/contents/text_contents.cc - mirrors/engine - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #include "impeller/entity/contents/text_contents.h"

 #include <optional>
 #include <type_traits>
 #include <utility>

 #include "impeller/core/formats.h"
 #include "impeller/core/sampler_descriptor.h"
 #include "impeller/entity/contents/content_context.h"
 #include "impeller/entity/entity.h"
 #include "impeller/geometry/path_builder.h"
 #include "impeller/renderer/render_pass.h"
 #include "impeller/renderer/sampler_library.h"
 #include "impeller/tessellator/tessellator.h"
 #include "impeller/typographer/glyph_atlas.h"
 #include "impeller/typographer/lazy_glyph_atlas.h"

 namespace impeller {

 TextContents::TextContents() = default;

 TextContents::~TextContents() = default;

 void TextContents::SetTextFrame(const TextFrame& frame) {
   frame_ = frame;
 }

 void TextContents::SetGlyphAtlas(std::shared_ptr<LazyGlyphAtlas> atlas) {
   lazy_atlas_ = std::move(atlas);
 }

 std::shared_ptr<GlyphAtlas> TextContents::ResolveAtlas(
     GlyphAtlas::Type type,
     std::shared_ptr<GlyphAtlasContext> atlas_context,
     std::shared_ptr<Context> context) const {
   FML_DCHECK(lazy_atlas_);
   if (lazy_atlas_) {
     return lazy_atlas_->CreateOrGetGlyphAtlas(type, std::move(atlas_context),
                                               std::move(context));
   }

   return nullptr;
 }

 void TextContents::SetColor(Color color) {
   color_ = color;
 }

 Color TextContents::GetColor() const {
   return color_.WithAlpha(color_.alpha * inherited_opacity_);
 }

 bool TextContents::CanInheritOpacity(const Entity& entity) const {
   return !frame_.MaybeHasOverlapping();
 }

 void TextContents::SetInheritedOpacity(Scalar opacity) {
   inherited_opacity_ = opacity;
 }

 void TextContents::SetOffset(Vector2 offset) {
   offset_ = offset;
 }

 std::optional<Rect> TextContents::GetCoverage(const Entity& entity) const {
   auto bounds = frame_.GetBounds();
   if (!bounds.has_value()) {
     return std::nullopt;
   }
   return bounds->TransformBounds(entity.GetTransformation());
 }

 static bool CommonRender(
     const ContentContext& renderer,
     const Entity& entity,
     RenderPass& pass,
     const Color& color,
     const TextFrame& frame,
     Vector2 offset,
     std::shared_ptr<GlyphAtlas>
         atlas,  // NOLINT(performance-unnecessary-value-param)
     Command& cmd) {
   using VS = GlyphAtlasPipeline::VertexShader;
   using FS = GlyphAtlasPipeline::FragmentShader;

   // Common vertex uniforms for all glyphs.
   VS::FrameInfo frame_info;

   frame_info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize());
   VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(frame_info));

   SamplerDescriptor sampler_desc;
   if (entity.GetTransformation().IsTranslationScaleOnly()) {
     sampler_desc.min_filter = MinMagFilter::kNearest;
     sampler_desc.mag_filter = MinMagFilter::kNearest;
   } else {
     // Currently, we only propagate the scale of the transform to the atlas
     // renderer, so if the transform has more than just a translation, we turn
     // on linear sampling to prevent crunchiness caused by the pixel grid not
     // being perfectly aligned.
     // The downside is that this slightly over-blurs rotated/skewed text.
     sampler_desc.min_filter = MinMagFilter::kLinear;
     sampler_desc.mag_filter = MinMagFilter::kLinear;
   }
   sampler_desc.mip_filter = MipFilter::kNearest;

   FS::FragInfo frag_info;
   frag_info.text_color = ToVector(color.Premultiply());
   FS::BindFragInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(frag_info));

   FS::BindGlyphAtlasSampler(
       cmd,                  // command
       atlas->GetTexture(),  // texture
       renderer.GetContext()->GetSamplerLibrary()->GetSampler(
           sampler_desc)  // sampler
   );

   // Common vertex information for all glyphs.
   // All glyphs are given the same vertex information in the form of a
   // unit-sized quad. The size of the glyph is specified in per instance data
   // and the vertex shader uses this to size the glyph correctly. The
   // interpolated vertex information is also used in the fragment shader to
   // sample from the glyph atlas.

   constexpr std::array<Point, 4> unit_points = {Point{0, 0}, Point{1, 0},
                                                 Point{0, 1}, Point{1, 1}};
   constexpr std::array<uint32_t, 6> indices = {0, 1, 2, 1, 2, 3};

   VertexBufferBuilder<typename VS::PerVertexData> vertex_builder;

   size_t count = 0;
   for (const auto& run : frame.GetRuns()) {
     count += run.GetGlyphPositions().size();
   }

   vertex_builder.Reserve(count * 4);
   vertex_builder.ReserveIndices(count * 6);

   uint32_t index_offset = 0u;
   for (auto i = 0u; i < count; i++) {
     for (const auto& index : indices) {
       vertex_builder.AppendIndex(index + index_offset);
     }
     index_offset += 4;
   }

   auto atlas_size =
       Point{static_cast<Scalar>(atlas->GetTexture()->GetSize().width),
             static_cast<Scalar>(atlas->GetTexture()->GetSize().height)};

   Vector2 screen_offset = (entity.GetTransformation() * offset).Round();

   for (const auto& run : frame.GetRuns()) {
     const Font& font = run.GetFont();

     for (const auto& glyph_position : run.GetGlyphPositions()) {
       FontGlyphPair font_glyph_pair{font, glyph_position.glyph};
       auto atlas_glyph_bounds = atlas->FindFontGlyphBounds(font_glyph_pair);
       if (!atlas_glyph_bounds.has_value()) {
         VALIDATION_LOG << "Could not find glyph position in the atlas.";
         return false;
       }

       // For each glyph, we compute two rectangles. One for the vertex positions
       // and one for the texture coordinates (UVs).

       auto uv_origin =
           (atlas_glyph_bounds->origin - Point(0.5, 0.5)) / atlas_size;
       auto uv_size = (atlas_glyph_bounds->size + Size(1, 1)) / atlas_size;

       // Rounding here prevents most jitter between glyphs in the run when
       // nearest sampling.
       auto screen_glyph_position =
           screen_offset +
           (entity.GetTransformation().Basis() *
            (glyph_position.position + glyph_position.glyph.bounds.origin))
               .Round();

       for (const auto& point : unit_points) {
         VS::PerVertexData vtx;

         if (entity.GetTransformation().IsTranslationScaleOnly()) {
           // Rouding up here prevents the bounds from becoming 1 pixel too small
           // when nearest sampling. This path breaks down for projections.
           vtx.position =
               screen_glyph_position + (entity.GetTransformation().Basis() *
                                        point * glyph_position.glyph.bounds.size)
                                           .Ceil();
         } else {
           vtx.position = entity.GetTransformation() *
                          Vector4(offset + glyph_position.position +
                                  glyph_position.glyph.bounds.origin +
                                  point * glyph_position.glyph.bounds.size);
         }
         vtx.uv = uv_origin + point * uv_size;
         vertex_builder.AppendVertex(vtx);
       }
     }
   }
   auto vertex_buffer =
       vertex_builder.CreateVertexBuffer(pass.GetTransientsBuffer());
   cmd.BindVertices(vertex_buffer);

   if (!pass.AddCommand(cmd)) {
     return false;
   }

   return true;
 }

 bool TextContents::Render(const ContentContext& renderer,
                           const Entity& entity,
                           RenderPass& pass) const {
   auto color = GetColor();
   if (color.IsTransparent()) {
     return true;
   }

   auto type = frame_.GetAtlasType();
   auto atlas = ResolveAtlas(type, renderer.GetGlyphAtlasContext(type),
                             renderer.GetContext());

   if (!atlas || !atlas->IsValid()) {
     VALIDATION_LOG << "Cannot render glyphs without prepared atlas.";
     return false;
   }

   // Information shared by all glyph draw calls.
   Command cmd;
   cmd.label = "TextFrame";
   auto opts = OptionsFromPassAndEntity(pass, entity);
   opts.primitive_type = PrimitiveType::kTriangle;
   if (type == GlyphAtlas::Type::kAlphaBitmap) {
     cmd.pipeline = renderer.GetGlyphAtlasPipeline(opts);
   } else {
     cmd.pipeline = renderer.GetGlyphAtlasColorPipeline(opts);
   }
   cmd.stencil_reference = entity.GetStencilDepth();

   return CommonRender(renderer, entity, pass, color, frame_, offset_, atlas,
                       cmd);
 }

 }  // namespace impeller
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#include "impeller/entity/contents/text_contents.h"

	#include <optional>
	#include <type_traits>
	#include <utility>

	#include "impeller/core/formats.h"
	#include "impeller/core/sampler_descriptor.h"
	#include "impeller/entity/contents/content_context.h"
	#include "impeller/entity/entity.h"
	#include "impeller/geometry/path_builder.h"
	#include "impeller/renderer/render_pass.h"
	#include "impeller/renderer/sampler_library.h"
	#include "impeller/tessellator/tessellator.h"
	#include "impeller/typographer/glyph_atlas.h"
	#include "impeller/typographer/lazy_glyph_atlas.h"

	namespace impeller {

	TextContents::TextContents() = default;

	TextContents::~TextContents() = default;

	void TextContents::SetTextFrame(const TextFrame& frame) {
	frame_ = frame;
	}

	void TextContents::SetGlyphAtlas(std::shared_ptr<LazyGlyphAtlas> atlas) {
	lazy_atlas_ = std::move(atlas);
	}

	std::shared_ptr<GlyphAtlas> TextContents::ResolveAtlas(
	GlyphAtlas::Type type,
	std::shared_ptr<GlyphAtlasContext> atlas_context,
	std::shared_ptr<Context> context) const {
	FML_DCHECK(lazy_atlas_);
	if (lazy_atlas_) {
	return lazy_atlas_->CreateOrGetGlyphAtlas(type, std::move(atlas_context),
	std::move(context));
	}

	return nullptr;
	}

	void TextContents::SetColor(Color color) {
	color_ = color;
	}

	Color TextContents::GetColor() const {
	return color_.WithAlpha(color_.alpha * inherited_opacity_);
	}

	bool TextContents::CanInheritOpacity(const Entity& entity) const {
	return !frame_.MaybeHasOverlapping();
	}

	void TextContents::SetInheritedOpacity(Scalar opacity) {
	inherited_opacity_ = opacity;
	}

	void TextContents::SetOffset(Vector2 offset) {
	offset_ = offset;
	}

	std::optional<Rect> TextContents::GetCoverage(const Entity& entity) const {
	auto bounds = frame_.GetBounds();
	if (!bounds.has_value()) {
	return std::nullopt;
	}
	return bounds->TransformBounds(entity.GetTransformation());
	}

	static bool CommonRender(
	const ContentContext& renderer,
	const Entity& entity,
	RenderPass& pass,
	const Color& color,
	const TextFrame& frame,
	Vector2 offset,
	std::shared_ptr<GlyphAtlas>
	atlas, // NOLINT(performance-unnecessary-value-param)
	Command& cmd) {
	using VS = GlyphAtlasPipeline::VertexShader;
	using FS = GlyphAtlasPipeline::FragmentShader;

	// Common vertex uniforms for all glyphs.
	VS::FrameInfo frame_info;

	frame_info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize());
	VS::BindFrameInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(frame_info));

	SamplerDescriptor sampler_desc;
	if (entity.GetTransformation().IsTranslationScaleOnly()) {
	sampler_desc.min_filter = MinMagFilter::kNearest;
	sampler_desc.mag_filter = MinMagFilter::kNearest;
	} else {
	// Currently, we only propagate the scale of the transform to the atlas
	// renderer, so if the transform has more than just a translation, we turn
	// on linear sampling to prevent crunchiness caused by the pixel grid not
	// being perfectly aligned.
	// The downside is that this slightly over-blurs rotated/skewed text.
	sampler_desc.min_filter = MinMagFilter::kLinear;
	sampler_desc.mag_filter = MinMagFilter::kLinear;
	}
	sampler_desc.mip_filter = MipFilter::kNearest;

	FS::FragInfo frag_info;
	frag_info.text_color = ToVector(color.Premultiply());
	FS::BindFragInfo(cmd, pass.GetTransientsBuffer().EmplaceUniform(frag_info));

	FS::BindGlyphAtlasSampler(
	cmd, // command
	atlas->GetTexture(), // texture
	renderer.GetContext()->GetSamplerLibrary()->GetSampler(
	sampler_desc) // sampler
	);

	// Common vertex information for all glyphs.
	// All glyphs are given the same vertex information in the form of a
	// unit-sized quad. The size of the glyph is specified in per instance data
	// and the vertex shader uses this to size the glyph correctly. The
	// interpolated vertex information is also used in the fragment shader to
	// sample from the glyph atlas.

	constexpr std::array<Point, 4> unit_points = {Point{0, 0}, Point{1, 0},
	Point{0, 1}, Point{1, 1}};
	constexpr std::array<uint32_t, 6> indices = {0, 1, 2, 1, 2, 3};

	VertexBufferBuilder<typename VS::PerVertexData> vertex_builder;

	size_t count = 0;
	for (const auto& run : frame.GetRuns()) {
	count += run.GetGlyphPositions().size();
	}

	vertex_builder.Reserve(count * 4);
	vertex_builder.ReserveIndices(count * 6);

	uint32_t index_offset = 0u;
	for (auto i = 0u; i < count; i++) {
	for (const auto& index : indices) {
	vertex_builder.AppendIndex(index + index_offset);
	}
	index_offset += 4;
	}

	auto atlas_size =
	Point{static_cast<Scalar>(atlas->GetTexture()->GetSize().width),
	static_cast<Scalar>(atlas->GetTexture()->GetSize().height)};

	Vector2 screen_offset = (entity.GetTransformation() * offset).Round();

	for (const auto& run : frame.GetRuns()) {
	const Font& font = run.GetFont();

	for (const auto& glyph_position : run.GetGlyphPositions()) {
	FontGlyphPair font_glyph_pair{font, glyph_position.glyph};
	auto atlas_glyph_bounds = atlas->FindFontGlyphBounds(font_glyph_pair);
	if (!atlas_glyph_bounds.has_value()) {
	VALIDATION_LOG << "Could not find glyph position in the atlas.";
	return false;
	}

	// For each glyph, we compute two rectangles. One for the vertex positions
	// and one for the texture coordinates (UVs).

	auto uv_origin =
	(atlas_glyph_bounds->origin - Point(0.5, 0.5)) / atlas_size;
	auto uv_size = (atlas_glyph_bounds->size + Size(1, 1)) / atlas_size;

	// Rounding here prevents most jitter between glyphs in the run when
	// nearest sampling.
	auto screen_glyph_position =
	screen_offset +
	(entity.GetTransformation().Basis() *
	(glyph_position.position + glyph_position.glyph.bounds.origin))
	.Round();

	for (const auto& point : unit_points) {
	VS::PerVertexData vtx;

	if (entity.GetTransformation().IsTranslationScaleOnly()) {
	// Rouding up here prevents the bounds from becoming 1 pixel too small
	// when nearest sampling. This path breaks down for projections.
	vtx.position =
	screen_glyph_position + (entity.GetTransformation().Basis() *
	point * glyph_position.glyph.bounds.size)
	.Ceil();
	} else {
	vtx.position = entity.GetTransformation() *
	Vector4(offset + glyph_position.position +
	glyph_position.glyph.bounds.origin +
	point * glyph_position.glyph.bounds.size);
	}
	vtx.uv = uv_origin + point * uv_size;
	vertex_builder.AppendVertex(vtx);
	}
	}
	}
	auto vertex_buffer =
	vertex_builder.CreateVertexBuffer(pass.GetTransientsBuffer());
	cmd.BindVertices(vertex_buffer);

	if (!pass.AddCommand(cmd)) {
	return false;
	}

	return true;
	}

	bool TextContents::Render(const ContentContext& renderer,
	const Entity& entity,
	RenderPass& pass) const {
	auto color = GetColor();
	if (color.IsTransparent()) {
	return true;
	}

	auto type = frame_.GetAtlasType();
	auto atlas = ResolveAtlas(type, renderer.GetGlyphAtlasContext(type),
	renderer.GetContext());

	if (!atlas \|\| !atlas->IsValid()) {
	VALIDATION_LOG << "Cannot render glyphs without prepared atlas.";
	return false;
	}

	// Information shared by all glyph draw calls.
	Command cmd;
	cmd.label = "TextFrame";
	auto opts = OptionsFromPassAndEntity(pass, entity);
	opts.primitive_type = PrimitiveType::kTriangle;
	if (type == GlyphAtlas::Type::kAlphaBitmap) {
	cmd.pipeline = renderer.GetGlyphAtlasPipeline(opts);
	} else {
	cmd.pipeline = renderer.GetGlyphAtlasColorPipeline(opts);
	}
	cmd.stencil_reference = entity.GetStencilDepth();

	return CommonRender(renderer, entity, pass, color, frame_, offset_, atlas,
	cmd);
	}

	} // namespace impeller