freetype_dart

Description:

freetype dart

freetype dart bindings
example

import 'dart:ffi';
import 'package:ffi/ffi.dart';
import 'package:freetype_dart/src/errors.dart';
import 'package:freetype_dart/src/extensions/extensions.dart';
import 'package:freetype_dart/src/generated_bindings.dart';
import 'dart:io';
import 'package:image/image.dart' as img;

void main(List<String> args) {
final dylib = DynamicLibrary.open(
Platform.isWindows ? 'libfreetype-6.dll' : 'libfreetype.so.6');

final ft = FreetypeBinding(dylib);

final library = calloc<FT_Library>();

var err = ft.FT_Init_FreeType(library);
if (err != FT_Err_Ok) {
print('err on Init FreeType');
}

final face = calloc<FT_Face>();
err = ft.FT_New_Face(library.value, "VeraMono.ttf".asCharP(), 0, face);

if (err == FT_Err_Unknown_File_Format) {
print("Font format is unsupported");
} else if (err == 1) {
print("Font file is missing or corrupted");
}

// Ensure an unicode characater map is loaded
err = ft.FT_Select_Charmap(face.value, ft_encoding_unicode);
print("FT_Select_Charmap $err");

// Select a character to render
var character = 'A';
int glyph_index = ft.FT_Get_Char_Index(face.value, character.codeUnitAt(0));
if (glyph_index == 0) {
print('código de caractere indefinido');
}
print("glyph_index $glyph_index");

err = ft.FT_Set_Pixel_Sizes(face.value, 0, 240); // Set font size to 24 pixels
print("FT_Set_Pixel_Sizes $err");

err = ft.FT_Load_Glyph(face.value, glyph_index, FT_LOAD_DEFAULT);
print("FT_Load_Glyph $err");

// // Render the glyph to a bitmap
err = ft.FT_Render_Glyph(
face.value.ref.glyph, FT_Render_Mode_.FT_RENDER_MODE_NORMAL);
print("FT_Render_Glyph $err");
FT_Bitmap bitmap = face.value.ref.glyph.ref.bitmap;

print(
"bitmap width ${bitmap.width} rows ${bitmap.rows} mode ${bitmap.pixel_mode} ${bitmap.pitch}");

var format = img.Format.uint8;

final buffer = bitmap.buffer
.cast<Int8>()
.asTypedList((bitmap.pitch * bitmap.rows).toInt());

// Create a 256x256 8-bit (default) rgb (default) image.
final image = img.Image.fromBytes(
width: bitmap.width,
height: bitmap.rows,
bytes: buffer.buffer,
numChannels: 1,
format: format);

// Encode the resulting image to the PNG image format.
final png = img.encodePng(image);
// Write the PNG formatted data to a file.
File('image.png').writeAsBytesSync(png);

ft.FT_Done_Face(face.value);
ft.FT_Done_FreeType(library.value);
}


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import 'dart:math';
import 'package:freetype_dart/src/wrapper/freetype.dart';
import 'dart:io';
import 'package:image/image.dart' as img;

void main(List<String> args) {
createPreview('VeraMono.ttf', 'VeraMono.png');
}

void createPreview(String fontFileName, String outputFileName,
{int width = 640,
int height = 480,
int fontSize = 24,
img.Color? backgroundColor}) {
final image = img.Image(width: width, height: height);
image.clear(backgroundColor ?? img.ColorRgb8(255, 255, 255));

final ft = Freetype();
final face = ft.newFace(fontFileName);
face.setCharSize(fontSize * 64, 0, 100, 0);

final text = face.familyName;
final numChars = text.length;

var targetHeight = height;
final pen = Vector(50 * 64, (targetHeight - 100) * 64);

final angle = (0.0 / 360) * 3.14159 * 2;

final matrix = Matrix(0, 0, 0, 0);
matrix.xx = (cos(angle) * 0x10000).toInt();
matrix.xy = (-sin(angle) * 0x10000).toInt();
matrix.yx = (sin(angle) * 0x10000).toInt();
matrix.yy = (cos(angle) * 0x10000).toInt();

for (var n = 0; n < numChars; n++) {
// set transformation
face.setTransform(matrix, pen);
// load glyph image into the slot (erase previous one)
final char = text.codeUnitAt(n);
final isLoad = face.loadChar(char, LoadFlag.RENDER);
if (isLoad == false) continue; // ignore errors
final glyph = face.glyph;
final bitmap = glyph.bitmap();
final x = glyph.bitmapLeft;
final y = targetHeight - glyph.bitmapTop;
drawBitmap(image, bitmap, x, y);
// increment pen position
pen.x += glyph.advance.x;
pen.y += glyph.advance.y;
}

final png = img.encodePng(image);
File(outputFileName).writeAsBytesSync(png);

face.free();
ft.free();
}

void drawBitmap(img.Image imageCtx, Bitmap bitmap, int x, int y) {
final w = bitmap.width;
final xMax = w;
final yMax = bitmap.rows;
final data = bitmap.buffer;

for (var p = 0; p < xMax; p++) {
for (var q = 0; q < yMax; q++) {
var i = x + p;
var j = y + q;
if (i < 0 || j < 0 || i >= imageCtx.width || j >= imageCtx.height) {
continue;
}
final idx = q * w + p;
// if (idx > data.length - 1) {
// continue;
// }
final val = data[idx];
final cor = img.ColorRgba8(84, 13, 110, val);
img.drawPixel(imageCtx, i, j, cor, maskChannel: img.Channel.luminance);
}
}
}

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