feat(surfacerenderer): optimized rendering pipeline

Author: Dax89

src/support/surfacerenderer.cpp

@@ -10,22 +10,53 @@ namespace {
 QFont g_font;
 qreal g_cell_w = 0;
 qreal g_cell_h = 0;
+qreal g_baseline = 0;
 
-void render_row(QPainter* p, RDRowSlice row, qreal y) {
-    for(int j = 0; j < static_cast<int>(rd_slice_length(row)); j++) {
-        RDCell c = rd_slice_at(row, j);
-        QColor fg = theme_provider::color(c.fg);
-        QColor bg = theme_provider::color(c.bg);
+void render_cells(QPainter* p, RDRowSlice row, usize start_x, qreal y) {
+    const usize LEN = rd_slice_length(row);
+    if(start_x >= LEN) return;
 
+    const qreal BASELINE = y + g_baseline;
+
+    QString text;
+    usize runstart = 0;
+    RDThemeKind runfg{}, runbg{};
+    bool inrun = false;
+
+    auto flush = [&]() {
+        if(text.isEmpty()) return;
+
+        QColor fg = theme_provider::color(runfg);
+        QColor bg = theme_provider::color(runbg);
         Q_ASSERT(fg.isValid());
         Q_ASSERT(bg.isValid());
 
-        QRectF r(j * g_cell_w, y, g_cell_w, g_cell_h);
+        const qreal X = static_cast<qreal>(runstart) * g_cell_w;
 
-        p->fillRect(r, bg);
+        p->fillRect(QRectF(X, y, text.size() * g_cell_w, g_cell_h), bg);
         p->setPen(fg);
-        p->drawText(r, Qt::AlignCenter, QChar{static_cast<char32_t>(c.cp)});
+        p->drawText(QPointF(X, BASELINE), text);
+
+        text.clear();
+    };
+
+    usize col = 0;
+
+    for(usize cx = start_x; cx < LEN; cx++, col++) {
+        RDCell c = rd_slice_at(row, cx);
+
+        if(!inrun || c.fg != runfg || c.bg != runbg) {
+            flush();
+            inrun = true;
+            runfg = c.fg;
+            runbg = c.bg;
+            runstart = col;
+        }
+
+        text.append(QChar{static_cast<char32_t>(c.cp)});
     }
+
+    flush();
 }
 
 } // namespace
@@ -36,6 +67,9 @@ void init() {
     QFontMetricsF fm{g_font};
     g_cell_w = fm.horizontalAdvance(" ");
     g_cell_h = fm.height();
+
+    const qreal LEADING = g_cell_h - (fm.ascent() + fm.descent());
+    g_baseline = (LEADING / 2.0) + fm.ascent();
 }
 
 RDSurfacePos hit_test(QPoint pt, quint64 start_x) {
@@ -55,35 +89,17 @@ void render(QPainter* p, RDSurface* surface, usize n, usize start_x) {
     p->setFont(surface_renderer::g_font);
 
     for(usize i = 0; i < n; i++) {
-        RDRowSlice row = rd_surface_get_row(surface, i);
-        qreal y = static_cast<qreal>(i) * surface_renderer::g_cell_h;
-
-        usize char_idx = start_x;
-
-        for(usize j = 0; char_idx < rd_slice_length(row); j++, char_idx++) {
-            RDCell c = rd_slice_at(row, char_idx);
-            QColor fg = theme_provider::color(c.fg);
-            QColor bg = theme_provider::color(c.bg);
-
-            Q_ASSERT(fg.isValid());
-            Q_ASSERT(bg.isValid());
-
-            QRectF r(static_cast<qreal>(j) * g_cell_w, y, g_cell_w, g_cell_h);
-
-            p->fillRect(r, bg);
-            p->setPen(fg);
-            p->drawText(r, Qt::AlignCenter, QChar{static_cast<char32_t>(c.cp)});
-        }
+        render_cells(p, rd_surface_get_row(surface, i), start_x,
+                     static_cast<qreal>(i) * g_cell_h);
     }
 }
 
 void render_block(QPainter* p, RDSurfaceGraph* surface, usize start, usize n) {
     p->setFont(g_font);
 
     for(usize i = 0; i < n; i++) {
-        RDRowSlice row = rd_surfacegraph_get_row(surface, start + i);
-        qreal y = static_cast<qreal>(i) * surface_renderer::g_cell_h;
-        surface_renderer::render_row(p, row, y);
+        render_cells(p, rd_surfacegraph_get_row(surface, start + i), 0,
+                     static_cast<qreal>(i) * g_cell_h);
     }
 }