Experimental: text editor
Proof of principle of a text editor written with Skia & SkShaper.
(Work In Progress)
Bug: skia:9020
Change-Id: I4fb837b719bc42fab8d8bdce2ca68fb9c1829d21
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/210381
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 92ab115..20293b7 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2453,4 +2453,16 @@
]
}
}
+
+ test_app("editor") {
+ is_shared_library = is_android
+ sources = [
+ "experimental/editor/editor_application.cpp",
+ ]
+ deps = [
+ ":sk_app",
+ ":skia",
+ "modules/skshaper",
+ ]
+ }
}
diff --git a/experimental/editor/editor_application.cpp b/experimental/editor/editor_application.cpp
new file mode 100644
index 0000000..a176bca
--- /dev/null
+++ b/experimental/editor/editor_application.cpp
@@ -0,0 +1,193 @@
+// Copyright 2019 Google LLC.
+// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+// [Work In Progress] Proof of principle of a text editor written with Skia & SkShaper.
+// https://bugs.skia.org/9020
+
+#include "include/core/SkExecutor.h"
+#include "include/core/SkPath.h"
+#include "include/core/SkPictureRecorder.h"
+#include "include/core/SkSurface.h"
+#include "include/core/SkTime.h"
+#include "include/effects/SkGradientShader.h"
+#include "modules/skshaper/include/SkShaper.h"
+#include "tools/sk_app/Application.h"
+#include "tools/sk_app/CommandSet.h"
+#include "tools/sk_app/Window.h"
+
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace {
+
+struct Timer {
+ double fTime;
+ const char* fDesc;
+ Timer(const char* desc = "") : fTime(SkTime::GetNSecs()), fDesc(desc) {}
+ ~Timer() { SkDebugf("%s: %d ms\n", fDesc, (int)((SkTime::GetNSecs() - fTime) * 1e-6)); }
+};
+
+struct TextLine {
+ TextLine(std::string s) : fText(std::move(s)) {}
+ std::string fText;
+ float fHeight = 0;
+ sk_sp<const SkTextBlob> fBlob;
+ bool fSelected = false; // Will allow selection of subset of text later.
+ // Also will track presence of cursor.
+
+ void shape(const SkFont& font, const SkShaper* shaper, float width) {
+ SkTextBlobBuilderRunHandler textBlobBuilder(fText.c_str(), {0, 0});
+ shaper->shape(fText.c_str(), fText.size(), font, true, width, &textBlobBuilder);
+ fHeight = std::max(textBlobBuilder.endPoint().y(), font.getSpacing());
+ fBlob = textBlobBuilder.makeBlob();
+ }
+};
+
+std::vector<TextLine> read_file(const char* path) {
+ std::vector<TextLine> ret;
+ if (path) {
+ std::ifstream stream(path);
+ for (std::string line; std::getline(stream, line);) {
+ ret.push_back(TextLine(line));
+ }
+ }
+ return ret;
+}
+
+struct EditorLayer : public sk_app::Window::Layer {
+ sk_app::Window* fParent = nullptr;
+ std::vector<TextLine> fLines;
+ const SkShaper* fShaper = nullptr;
+ int fMargin = 10;
+ int fPos = 10;
+ int fWidth = 0;
+ int fHeight = 0;
+ SkFont fFont{nullptr, 24};
+
+ EditorLayer(std::vector<TextLine> lines, SkShaper* shaper)
+ : fLines(std::move(lines)), fShaper(shaper) {}
+
+ void onPaint(SkSurface* surface) override {
+ Timer timer("painting");
+ SkColor background = SkColorSetARGB(0xFF, 0xCC, 0xCC, 0xCC);
+ SkColor foreground = SkColorSetARGB(0xFF, 0x00, 0x00, 0x00);
+ SkCanvas* c = surface->getCanvas();
+ c->clipRect({0, 0, (float)fWidth, (float)fHeight});
+ c->clear(background);
+ float y = fPos;
+ SkPaint p;
+ p.setColor(foreground);
+ SkPaint diff;
+ diff.setColor(SK_ColorWHITE);
+ diff.setBlendMode(SkBlendMode::kDifference);
+ float width = (float)(fWidth - 2 * fMargin);
+ for (const TextLine& line : fLines) {
+ if (line.fBlob) {
+ c->drawTextBlob(line.fBlob.get(), fMargin, y, p);
+ }
+ if (line.fSelected) {
+ c->drawRect(SkRect{(float)fMargin, y, width, y + line.fHeight}, diff);
+ }
+ y += line.fHeight;
+ }
+ }
+
+ void reshape() {
+ Timer timer("shaping");
+ float width = (float)(fWidth - 2 * fMargin);
+ #ifdef SK_EDITOR_GO_FAST
+ SkSemaphore semaphore;
+ std::unique_ptr<SkExecutor> executor = SkExecutor::MakeFIFOThreadPool(100);
+ for (TextLine& line : fLines) {
+ executor->add([&]() {
+ auto shaper = SkShaper::Make();
+ line.shape(fFont, shaper.get(), width);
+ semaphore.signal();
+ });
+ }
+ for (const TextLine& l : fLines) { semaphore.wait(); }
+ #else
+ for (TextLine& line : fLines) {
+ line.shape(fFont, fShaper, width);
+ }
+ #endif
+ }
+
+ void onResize(int width, int height) override {
+ if (SkISize{fWidth, fHeight} != SkISize{width, height}) {
+ fHeight = height;
+ if (width != fWidth) {
+ fWidth = width;
+ this->reshape();
+ }
+ if (fParent) {
+ fParent->inval();
+ }
+ }
+ }
+
+ void onAttach(sk_app::Window* w) override { fParent = w; }
+
+ bool onMouseWheel(float delta, uint32_t modifiers) override {
+ int newpos = std::min(fPos + (int)(delta * fFont.getSpacing()), fMargin);
+ if (newpos != fPos) {
+ fPos = newpos;
+ if (fParent) { fParent->inval(); }
+ return true;
+ }
+ return false;
+ }
+
+ bool onMouse(int x, int y, sk_app::Window::InputState state, uint32_t modifiers) override {
+ if (sk_app::Window::kDown_InputState == state) {
+ y -= fPos;
+ if (y >= 0) {
+ for (TextLine& line : fLines) {
+ if (y < line.fHeight) {
+ line.fSelected = !line.fSelected;
+ SkDebugf(" %d %d\n", x - (int)fMargin, y);
+ fParent->inval();
+ break;
+ }
+ y -= line.fHeight;
+ }
+ }
+ return true;
+ }
+ return false;
+ }
+};
+
+struct EditorApplication : public sk_app::Application {
+ std::unique_ptr<SkShaper> fShaper;
+ std::unique_ptr<sk_app::Window> fWindow;
+ std::unique_ptr<EditorLayer> fLayer;
+ sk_app::CommandSet fCommandSet;
+
+ EditorApplication(const char* path, void* platformData)
+ : fShaper(SkShaper::Make())
+ , fWindow(sk_app::Window::CreateNativeWindow(platformData))
+ {
+ fWindow->attach(sk_app::Window::kRaster_BackendType);
+ fLayer.reset(new EditorLayer(read_file(path), fShaper.get()));
+ fWindow->pushLayer(fLayer.get());
+ fCommandSet.attach(fWindow.get());
+ fWindow->show();
+ fLayer->onResize(fWindow->width(), fWindow->height());
+ }
+ ~EditorApplication() override { fWindow->detach(); }
+
+ void onIdle() override {}
+};
+
+} // namespace
+
+sk_app::Application* sk_app::Application::Create(int argc, char** argv, void* dat) {
+ if (argc > 1) {
+ return new EditorApplication(argv[1], dat);
+ }
+ return new EditorApplication(nullptr, dat);
+}
