Initial commit of Minikin library

This is the initial draft of Minikin, a library intended to perform text
layout functions. This version does basic weight selection and font runs
for scripts, and also has a simple renderer for drawing into bitmaps,
but is lacking measurement, line breaking, and a number of other
important features. It also lacks caching and other performance
refinements.

Change-Id: I789a2e47d11d71202dc84b4751b51a5e2cd9c451

1 files changed, 89 insertions, 0 deletions

diff --git a/include/minikin/Layout.h b/include/minikin/Layout.h
new file mode 100644
index 0000000..7a6c6cf
--- /dev/null
+++ b/include/minikin/Layout.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MINIKIN_LAYOUT_H
+#define MINIKIN_LAYOUT_H
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+#include <hb.h>
+
+#include <vector>
+
+#include <minikin/CssParse.h>
+#include <minikin/FontCollection.h>
+
+namespace android {
+
+// The Bitmap class is for debugging. We'll probably move it out
+// of here into a separate lightweight software rendering module
+// (optional, as we'd hope most clients would do their own)
+class Bitmap {
+public:
+    Bitmap(int width, int height);
+    ~Bitmap();
+    void writePnm(std::ofstream& o) const;
+    void drawGlyph(const FT_Bitmap& bitmap, int x, int y);
+private:
+    int width;
+    int height;
+    uint8_t* buf;
+};
+
+struct LayoutGlyph {
+    // index into mFaces and mHbFonts vectors. We could imagine
+    // moving this into a run length representation, because it's
+    // more efficient for long strings, and we'll probably need
+    // something like that for paint attributes (color, underline,
+    // fake b/i, etc), as having those per-glyph is bloated.
+    int font_ix;
+
+    unsigned int glyph_id;
+    float x;
+    float y;
+};
+
+class Layout {
+public:
+    void dump() const;
+    void setFontCollection(const FontCollection *collection);
+    void doLayout(const uint16_t* buf, size_t nchars);
+    void draw(Bitmap*, int x0, int y0) const;
+    void setProperties(const std::string css);
+
+    // This must be called before any invocations.
+	// TODO: probably have a factory instead
+    static void init();
+private:
+    // Find a face in the mFaces vector, or create a new entry
+    int findFace(FT_Face face);
+
+    CssProperties mProps;  // TODO: want spans
+    std::vector<LayoutGlyph> mGlyphs;
+
+    // In future, this will be some kind of mapping from the
+    // identifier used to represent font-family to a font collection.
+    // But for the time being, it should be ok to have just one
+    // per layout.
+    const FontCollection *mCollection;
+    std::vector<FT_Face> mFaces;
+    std::vector<hb_font_t *> mHbFonts;
+};
+
+}  // namespace android
+
+#endif  // MINIKIN_LAYOUT_H