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Setup methods and variables to accommodate actual intrinsic width algorithms.

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Change-Id: I7295a970488052f9b471617518afd7a757d8f5c0
This commit is contained in:
Gary Qian 2017-07-14 18:22:20 -07:00
parent 13f2e067c6
commit 1a68f70b47
2 changed files with 46 additions and 16 deletions
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53
engine/src/flutter/src/paragraph.cc
View File

@ -203,8 +203,8 @@ void Paragraph::Layout(double width, bool force) {
double line_width = 0.0f;
std::vector<SkScalar> x_queue;
double justify_spacing = 0;
double prev_word_pos = 0;
// Each blob.
std::vector<const SkTextBlobBuilder::RunBuffer*> buffers;
std::vector<size_t> buffer_sizes;
int word_count = 0;
@ -327,17 +327,6 @@ void Paragraph::Layout(double width, bool force) {
++blob_index) {
const size_t glyph_index = blob_start + blob_index;
buffers.back()->glyphs[blob_index] = layout.getGlyphId(glyph_index);
// Check if the current Glyph is a whitespace and handle multiple
// whitespaces in a row.
if (whitespace_set_.count(layout.getGlyphId(glyph_index)) > 0) {
// Only increment word_count if it is the first in a series of
// whitespaces.
if (whitespace_ended)
++word_count;
whitespace_ended = false;
} else {
whitespace_ended = true;
}
const size_t pos_index = 2 * blob_index;
@ -347,10 +336,36 @@ void Paragraph::Layout(double width, bool force) {
buffers.back()->pos[pos_index]);
buffers.back()->pos[pos_index + 1] = layout.getY(glyph_index);
// Check if the current Glyph is a whitespace and handle multiple
// whitespaces in a row.
if (whitespace_set_.count(layout.getGlyphId(glyph_index)) > 0) {
// Only increment word_count if it is the first in a series of
// whitespaces.
if (whitespace_ended) {
++word_count;
word_widths_.push_back(buffers.back()->pos[pos_index] +
layout.getCharAdvance(glyph_index) -
prev_word_pos);
prev_word_pos = buffers.back()->pos[pos_index] +
layout.getCharAdvance(glyph_index);
}
whitespace_ended = false;
} else {
whitespace_ended = true;
}
letter_spacing_offset += run.style.letter_spacing;
}
blob_start += blob_length;
// Add on the last word if the blob break was not on whitespace.
if (whitespace_ended) {
word_widths_.push_back(
layout.getX(blob_start - 1) + letter_spacing_offset -
run.style.letter_spacing + layout.getCharAdvance(blob_start - 1) -
prev_word_pos);
}
// Subtract letter offset to avoid big gap at end of run. This my be
// removed depending on the specifications for letter spacing.
// letter_spacing_offset -= run.style.letter_spacing;
@ -412,7 +427,7 @@ void Paragraph::Layout(double width, bool force) {
max_descent = 0.0f;
x = 0.0f;
letter_spacing_offset = 0.0f;
// word_count = 0;
prev_word_pos = 0;
line_width = 0.0f;
break_index += 1;
lines_++;
@ -440,6 +455,7 @@ void Paragraph::Layout(double width, bool force) {
buffer_sizes.size() > 0) {
JustifyLine(buffers, buffer_sizes, word_count, justify_spacing, -1);
}
CalculateIntrinsicWidths();
}
// Amends the buffers to incorporate justification.
@ -492,13 +508,22 @@ double Paragraph::GetIdeographicBaseline() const {
return ideographic_baseline_;
}
void Paragraph::CalculateIntrinsicWidths() {
for (size_t i = 0; i < word_widths_.size(); ++i) {
max_intrinsic_width_ += word_widths_[i];
}
// TODO(garyq): Implement the DP algorithm version instead of this stand in!
min_intrinsic_width_ = max_intrinsic_width_ / paragraph_style_.max_lines;
}
double Paragraph::GetMaxIntrinsicWidth() const {
return max_intrinsic_width_;
}
double Paragraph::GetMinIntrinsicWidth() const {
// TODO(garyq): This is a lower bound. Actual value may be slightly higher.
return max_intrinsic_width_ / paragraph_style_.max_lines;
return min_intrinsic_width_;
}
size_t Paragraph::TextSize() const {

9
engine/src/flutter/src/paragraph.h
View File

@ -115,8 +115,11 @@ class Paragraph {
SkScalar height_ = 0.0f;
double width_ = 0.0f;
size_t lines_ = 0;
double max_intrinsic_width_ = 0.0f;
double min_intrinsic_width_ = 0.0f;
double max_intrinsic_width_ = -1;
double min_intrinsic_width_ = -1;
// TODO(garyq): Instead of using whitespace to delimit "words", use the
// results of minikin breaker.
std::vector<double> word_widths_;
double alphabetic_baseline_ = FLT_MAX;
double ideographic_baseline_ = FLT_MAX;
bool needs_layout_ = true;
@ -167,6 +170,8 @@ class Paragraph {
double y_offset,
double width);
void CalculateIntrinsicWidths();
FTL_DISALLOW_COPY_AND_ASSIGN(Paragraph);
};