126 lines
3.2 KiB
Objective-C
126 lines
3.2 KiB
Objective-C
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#import "ARTText.h"
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#import <CoreText/CoreText.h>
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@implementation ARTText
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- (void)setAlignment:(CTTextAlignment)alignment
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{
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[self invalidate];
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_alignment = alignment;
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}
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static void ARTFreeTextFrame(ARTTextFrame frame)
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{
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if (frame.count) {
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// We must release each line before freeing up this struct
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for (int i = 0; i < frame.count; i++) {
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CFRelease(frame.lines[i]);
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}
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free(frame.lines);
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free(frame.widths);
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}
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}
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- (void)setTextFrame:(ARTTextFrame)frame
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{
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if (frame.lines != _textFrame.lines) {
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ARTFreeTextFrame(_textFrame);
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}
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[self invalidate];
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_textFrame = frame;
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}
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- (void)dealloc
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{
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ARTFreeTextFrame(_textFrame);
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}
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- (void)renderLayerTo:(CGContextRef)context
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{
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ARTTextFrame frame = self.textFrame;
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if ((!self.fill && !self.stroke) || !frame.count) {
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return;
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}
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// to-do: draw along a path
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CGTextDrawingMode mode = kCGTextStroke;
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if (self.fill) {
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if ([self.fill applyFillColor:context]) {
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mode = kCGTextFill;
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} else {
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for (int i = 0; i < frame.count; i++) {
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CGContextSaveGState(context);
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// Inverse the coordinate space since CoreText assumes a bottom-up coordinate space
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CGContextScaleCTM(context, 1.0, -1.0);
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CGContextSetTextDrawingMode(context, kCGTextClip);
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[self renderLineTo:context atIndex:i];
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// Inverse the coordinate space back to the original before filling
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CGContextScaleCTM(context, 1.0, -1.0);
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[self.fill paint:context];
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// Restore the state so that the next line can be clipped separately
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CGContextRestoreGState(context);
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}
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if (!self.stroke) {
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return;
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}
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}
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}
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if (self.stroke) {
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CGContextSetStrokeColorWithColor(context, self.stroke);
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CGContextSetLineWidth(context, self.strokeWidth);
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CGContextSetLineCap(context, self.strokeCap);
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CGContextSetLineJoin(context, self.strokeJoin);
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ARTCGFloatArray dash = self.strokeDash;
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if (dash.count) {
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CGContextSetLineDash(context, 0, dash.array, dash.count);
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}
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if (mode == kCGTextFill) {
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mode = kCGTextFillStroke;
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}
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}
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CGContextSetTextDrawingMode(context, mode);
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// Inverse the coordinate space since CoreText assumes a bottom-up coordinate space
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CGContextScaleCTM(context, 1.0, -1.0);
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for (int i = 0; i < frame.count; i++) {
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[self renderLineTo:context atIndex:i];
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}
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}
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- (void)renderLineTo:(CGContextRef)context atIndex:(int)index
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{
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ARTTextFrame frame = self.textFrame;
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CGFloat shift;
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switch (self.alignment) {
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case kCTTextAlignmentRight:
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shift = frame.widths[index];
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break;
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case kCTTextAlignmentCenter:
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shift = (frame.widths[index] / 2);
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break;
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default:
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shift = 0;
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break;
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}
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// We should consider snapping this shift to device pixels to improve rendering quality
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// when a line has subpixel width.
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CGContextSetTextPosition(context, -shift, -frame.baseLine - frame.lineHeight * index);
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CTLineRef line = frame.lines[index];
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CTLineDraw(line, context);
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}
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@end
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