add textutils

These are meant to enable several things (eventually)

- fission Align off of paint
- fission TextEncoding off of paint
- fission SkFont of of paint

The first one is explicitly enabled here. The others will (I plan) follow later.

The final state of the world (the goal)
- paint has no font-ish parameters (no typeface or size)
- font has no paint-ish parameters (no aa or lcd)
- neither has alignment or encoding

Bug: skia:8493, skia:8501
Change-Id: I5fcb945b6bcab30ef5e7019dfccb682661f56230
Reviewed-on: https://skia-review.googlesource.com/c/165061
Auto-Submit: Mike Reed <[email protected]>
Reviewed-by: Mike Reed <[email protected]>
Commit-Queue: Mike Reed <[email protected]>

gm/aaxfermodes.cpp

@@ -10,6 +10,7 @@
 #include "SkColorPriv.h"
 #include "SkPath.h"
 #include "SkShader.h"
+#include "SkTextUtils.h"
 
 enum {
     kXfermodeCount = (int)SkBlendMode::kLastMode + 1 + 1,   // extra for arith
@@ -106,14 +107,14 @@ class AAXfermodesGM : public skiagm::GM {
             canvas->save();
 
             if (kShape_Pass == drawingPass) {
-                fLabelPaint.setTextAlign(SkPaint::kCenter_Align);
-                canvas->drawString("Src Unknown",
+                SkTextUtils::DrawString(canvas, "Src Unknown",
                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2,
-                        kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3, fLabelPaint);
-                canvas->drawString("Src Opaque",
+                        kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3, fLabelPaint,
+                                        SkPaint::kCenter_Align);
+                SkTextUtils::DrawString(canvas, "Src Opaque",
                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2 +
                         kPaintSpacing, kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3,
-                        fLabelPaint);
+                        fLabelPaint, SkPaint::kCenter_Align);
             }
 
             canvas->translate(0, kSubtitleSpacing + kShapeSpacing/2);
@@ -179,23 +180,24 @@ class AAXfermodesGM : public skiagm::GM {
         SkPaint titlePaint(fLabelPaint);
         titlePaint.setTextSize(9 * titlePaint.getTextSize() / 8);
         titlePaint.setFakeBoldText(true);
-        titlePaint.setTextAlign(SkPaint::kCenter_Align);
-        canvas->drawString("Porter Duff",
-                         kLabelSpacing + 4 * kShapeTypeSpacing,
-                         kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
-        canvas->drawString("Advanced",
-                         kXfermodeTypeSpacing + kLabelSpacing + 4 * kShapeTypeSpacing,
-                         kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
+        SkTextUtils::DrawString(canvas, "Porter Duff",
+                                kLabelSpacing + 4 * kShapeTypeSpacing,
+                                kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint,
+                                SkPaint::kCenter_Align);
+        SkTextUtils::DrawString(canvas, "Advanced",
+                                kXfermodeTypeSpacing + kLabelSpacing + 4 * kShapeTypeSpacing,
+                                kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint,
+                                SkPaint::kCenter_Align);
 
         draw_pass(canvas, kShape_Pass);
         canvas->restore();
     }
 
     void drawModeName(SkCanvas* canvas, SkBlendMode mode) {
         const char* modeName = SkBlendMode_Name(mode);
-        fLabelPaint.setTextAlign(SkPaint::kRight_Align);
-        canvas->drawString(modeName, kLabelSpacing - kShapeSize / 4,
-                         fLabelPaint.getTextSize() / 4, fLabelPaint);
+        SkTextUtils::DrawString(canvas, modeName, kLabelSpacing - kShapeSize / 4,
+                                fLabelPaint.getTextSize() / 4, fLabelPaint,
+                                SkPaint::kRight_Align);
     }
 
     void setupShapePaint(SkCanvas* canvas, SkColor color, SkBlendMode mode, SkPaint* paint) {

gm/androidblendmodes.cpp

@@ -8,6 +8,7 @@
 #include "gm.h"
 #include "sk_tool_utils.h"
 #include "SkBitmap.h"
+#include "SkTextUtils.h"
 
 namespace skiagm {
 
@@ -67,7 +68,6 @@ class AndroidBlendModesGM : public GM {
         SkPaint textPaint;
         textPaint.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&textPaint);
-        textPaint.setTextAlign(SkPaint::kCenter_Align);
 
         sk_tool_utils::draw_checkerboard(canvas,
                                          kWhite,
@@ -94,10 +94,10 @@ class AndroidBlendModesGM : public GM {
             this->drawTile(canvas, xOffset, yOffset, mode);
             canvas->restoreToCount(saveCount);
 
-            canvas->drawString(SkBlendMode_Name(mode),
+            SkTextUtils::DrawString(canvas, SkBlendMode_Name(mode),
                                xOffset + kBitmapSize/2.0f,
                                yOffset + kBitmapSize,
-                               textPaint);
+                               textPaint, SkPaint::kCenter_Align);
 
             xOffset += 256;
             if (xOffset >= 1024) {

gm/tilemodes.cpp

@@ -11,6 +11,7 @@
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkShader.h"
+#include "SkTextUtils.h"
 #include "SkUTF.h"
 // effects
 #include "SkGradientShader.h"
@@ -104,8 +105,7 @@ class TilingGM : public skiagm::GM {
                 p.setDither(true);
                 str.printf("[%s,%s]", gModeNames[kx], gModeNames[ky]);
 
-                p.setTextAlign(SkPaint::kCenter_Align);
-                canvas->drawString(str, x + r.width()/2, y, p);
+                SkTextUtils::DrawString(canvas, str, x + r.width()/2, y, p, SkPaint::kCenter_Align);
 
                 x += r.width() * 4 / 3;
             }
@@ -223,22 +223,20 @@ class Tiling2GM : public skiagm::GM {
         SkPaint p;
         p.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&p);
-        p.setTextAlign(SkPaint::kCenter_Align);
 
         for (size_t kx = 0; kx < SK_ARRAY_COUNT(gModes); kx++) {
             SkString str(gModeNames[kx]);
-            canvas->drawString(str, x + r.width()/2, y, p);
+            SkTextUtils::DrawString(canvas, str, x + r.width()/2, y, p, SkPaint::kCenter_Align);
             x += r.width() * 4 / 3;
         }
 
         y += SkIntToScalar(16) + h;
-        p.setTextAlign(SkPaint::kRight_Align);
 
         for (size_t ky = 0; ky < SK_ARRAY_COUNT(gModes); ky++) {
             x = SkIntToScalar(16) + w;
 
             SkString str(gModeNames[ky]);
-            canvas->drawString(str, x, y + h/2, p);
+            SkTextUtils::DrawString(canvas, str, x, y + h/2, p, SkPaint::kRight_Align);
 
             x += SkIntToScalar(50);
             for (size_t kx = 0; kx < SK_ARRAY_COUNT(gModes); kx++) {

gm/tilemodes_scaled.cpp

@@ -11,6 +11,7 @@
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkShader.h"
+#include "SkTextUtils.h"
 #include "SkUTF.h"
 
 // effects
@@ -106,8 +107,8 @@ class ScaledTilingGM : public skiagm::GM {
                 sk_tool_utils::set_portable_typeface(&p);
                 str.printf("[%s,%s]", gModeNames[kx], gModeNames[ky]);
 
-                p.setTextAlign(SkPaint::kCenter_Align);
-                canvas->drawString(str, scale*(x + r.width()/2), y, p);
+                SkTextUtils::DrawString(canvas, str, scale*(x + r.width()/2), y, p,
+                                        SkPaint::kCenter_Align);
 
                 x += r.width() * 4 / 3;
             }
@@ -224,22 +225,20 @@ class ScaledTiling2GM : public skiagm::GM {
         SkPaint p;
         p.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&p);
-        p.setTextAlign(SkPaint::kCenter_Align);
 
         for (size_t kx = 0; kx < SK_ARRAY_COUNT(gModes); kx++) {
             SkString str(gModeNames[kx]);
-            canvas->drawString(str, x + r.width()/2, y, p);
+            SkTextUtils::DrawString(canvas, str, x + r.width()/2, y, p, SkPaint::kCenter_Align);
             x += r.width() * 4 / 3;
         }
 
         y += SkIntToScalar(16) + h;
-        p.setTextAlign(SkPaint::kRight_Align);
 
         for (size_t ky = 0; ky < SK_ARRAY_COUNT(gModes); ky++) {
             x = SkIntToScalar(16) + w;
 
             SkString str(gModeNames[ky]);
-            canvas->drawString(str, x, y + h/2, p);
+            SkTextUtils::DrawString(canvas, str, x, y + h/2, p, SkPaint::kRight_Align);
 
             x += SkIntToScalar(50);
             for (size_t kx = 0; kx < SK_ARRAY_COUNT(gModes); kx++) {

gm/windowrectangles.cpp

@@ -9,6 +9,7 @@
 #include "sk_tool_utils.h"
 #include "SkClipStack.h"
 #include "SkRRect.h"
+#include "SkTextUtils.h"
 
 #include "GrAppliedClip.h"
 #include "GrCaps.h"
@@ -265,7 +266,6 @@ void WindowRectanglesMaskGM::stencilCheckerboard(GrRenderTargetContext* rtc, boo
 void WindowRectanglesMaskGM::fail(SkCanvas* canvas) {
     SkPaint paint;
     paint.setAntiAlias(true);
-    paint.setTextAlign(SkPaint::kCenter_Align);
     paint.setTextSize(20);
     sk_tool_utils::set_portable_typeface(&paint);
 
@@ -275,8 +275,9 @@ void WindowRectanglesMaskGM::fail(SkCanvas* canvas) {
     canvas->clipRect(SkRect::Make(kCoverRect));
     canvas->clear(SK_ColorWHITE);
 
-    canvas->drawString(errorMsg, SkIntToScalar((kCoverRect.left() + kCoverRect.right())/2),
-                     SkIntToScalar((kCoverRect.top() + kCoverRect.bottom())/2 - 10), paint);
+    SkTextUtils::DrawString(canvas, errorMsg, SkIntToScalar((kCoverRect.left() + kCoverRect.right())/2),
+                     SkIntToScalar((kCoverRect.top() + kCoverRect.bottom())/2 - 10), paint,
+                            SkPaint::kCenter_Align);
 }
 
 DEF_GM( return new WindowRectanglesMaskGM(); )

gm/xfermodes.cpp

@@ -9,6 +9,7 @@
 #include "sk_tool_utils.h"
 #include "SkBitmap.h"
 #include "SkShader.h"
+#include "SkTextUtils.h"
 
 enum SrcType {
     //! A WxH image with a rectangle in the lower right.
@@ -227,7 +228,6 @@ class XfermodesGM : public skiagm::GM {
         SkPaint labelP;
         labelP.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&labelP);
-        labelP.setTextAlign(SkPaint::kCenter_Align);
 
         const int W = 5;
 
@@ -258,8 +258,8 @@ class XfermodesGM : public skiagm::GM {
 
 #if 1
                 const char* label = SkBlendMode_Name(gModes[i].fMode);
-                canvas->drawString(label,
-                                 x + w/2, y - labelP.getTextSize()/2, labelP);
+                SkTextUtils::DrawString(canvas, label, x + w/2, y - labelP.getTextSize()/2,
+                                        labelP, SkPaint::kCenter_Align);
 #endif
                 x += w + SkIntToScalar(10);
                 if ((i % W) == W - 1) {

gm/xfermodes2.cpp

@@ -10,6 +10,7 @@
 #include "SkShader.h"
 #include "SkBlendModePriv.h"
 #include "SkColorPriv.h"
+#include "SkTextUtils.h"
 
 namespace skiagm {
 
@@ -35,7 +36,6 @@ class Xfermodes2GM : public GM {
         SkPaint labelP;
         labelP.setAntiAlias(true);
         sk_tool_utils::set_portable_typeface(&labelP);
-        labelP.setTextAlign(SkPaint::kCenter_Align);
 
         const int W = 6;
 
@@ -72,8 +72,9 @@ class Xfermodes2GM : public GM {
             canvas->restore();
 
 #if 1
-            canvas->drawString(SkBlendMode_Name(mode),
-                               x + w/2, y - labelP.getTextSize()/2, labelP);
+            SkTextUtils::DrawString(canvas, SkBlendMode_Name(mode),
+                                    x + w/2, y - labelP.getTextSize()/2, labelP,
+                                    SkPaint::kCenter_Align);
 #endif
             x += w + SkIntToScalar(10);
             if ((m % W) == W - 1) {

gm/xfermodes3.cpp

@@ -12,7 +12,7 @@
 #include "SkSurface.h"
 #include "SkBlendModePriv.h"
 #include "SkColorPriv.h"
-
+#include "SkTextUtils.h"
 #include "GrContext.h"
 
 namespace skiagm {

gn/utils.gni

@@ -63,6 +63,7 @@ skia_utils_sources = [
   "$_src/utils/SkShadowTessellator.cpp",
   "$_src/utils/SkShadowTessellator.h",
   "$_src/utils/SkShadowUtils.cpp",
+  "$_src/utils/SkTextUtils.cpp",
   "$_src/utils/SkThreadUtils_pthread.cpp",
   "$_src/utils/SkThreadUtils_win.cpp",
   "$_src/utils/SkUTF.cpp",

include/utils/SkTextUtils.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkTextUtils_DEFINED
+#define SkTextUtils_DEFINED
+
+#include "SkCanvas.h"
+#include "SkPaint.h"
+#include "SkFont.h"
+#include "SkString.h"
+
+class SkTextUtils {
+public:
+    static void DrawText(SkCanvas*, const void* text, size_t size, SkScalar x, SkScalar y,
+                          const SkPaint&, SkPaint::Align = SkPaint::kLeft_Align);
+
+    static void DrawString(SkCanvas* canvas, const char text[], SkScalar x, SkScalar y,
+                           const SkPaint& paint, SkPaint::Align align = SkPaint::kLeft_Align) {
+        DrawText(canvas, text, strlen(text), x, y, paint, align);
+    }
+    static void DrawString(SkCanvas* canvas, const SkString& str, SkScalar x, SkScalar y,
+                           const SkPaint& paint, SkPaint::Align align = SkPaint::kLeft_Align) {
+        DrawText(canvas, str.c_str(), str.size(), x, y, paint, align);
+    }
+};
+
+#endif

src/utils/SkTextUtils.cpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2018 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkTextUtils.h"
+
+void SkTextUtils::DrawText(SkCanvas* canvas, const void* text, size_t size, SkScalar x, SkScalar y,
+                            const SkPaint& origPaint, SkPaint::Align align) {
+    int count = origPaint.countText(text, size);
+    if (!count) {
+        return;
+    }
+
+    SkPaint paint(origPaint);
+    SkAutoSTArray<32, uint16_t> glyphStorage;
+    const uint16_t* glyphs;
+
+    if (paint.getTextEncoding() != SkPaint::kGlyphID_TextEncoding) {
+        glyphStorage.reset(count);
+        paint.textToGlyphs(text, size, glyphStorage.get());
+        glyphs = glyphStorage.get();
+        paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
+    } else {
+        glyphs = static_cast<const uint16_t*>(text);
+    }
+
+    SkAutoSTArray<32, SkScalar> widthStorage(count);
+    SkScalar* widths = widthStorage.get();
+    paint.getTextWidths(glyphs, count * sizeof(uint16_t), widths);
+
+    if (align != SkPaint::kLeft_Align) {
+        SkScalar offset = 0;
+        for (int i = 0; i < count; ++i) {
+            offset += widths[i];
+        }
+        if (align == SkPaint::kCenter_Align) {
+            offset *= 0.5f;
+        }
+        x -= offset;
+    }
+
+    // Turn widths into h-positions
+    for (int i = 0; i < count; ++i) {
+        SkScalar w = widths[i];
+        widths[i] = x;
+        x += w;
+    }
+    canvas->drawPosTextH(glyphs, count * sizeof(uint16_t), widths, y, paint);
+}
+