First Commit

libui-ng/darwin/drawtext.m

@@ -0,0 +1,232 @@
+// 7 march 2018
+#import "uipriv_darwin.h"
+#import "draw.h"
+#import "attrstr.h"
+
+// problem: for a CTFrame made from an empty string, the CTLine array will be empty, and we will crash when doing anything requiring a CTLine
+// solution: for those cases, maintain a separate framesetter just for computing those things
+// in the usual case, the separate copy will just be identical to the regular one, with extra references to everything within
+@interface uiprivTextFrame : NSObject {
+	CFAttributedStringRef attrstr;
+	NSArray *backgroundParams;
+	CTFramesetterRef framesetter;
+	CGSize size;
+	CGPathRef path;
+	CTFrameRef frame;
+}
+- (id)initWithLayoutParams:(uiDrawTextLayoutParams *)p;
+- (void)draw:(uiDrawContext *)c textLayout:(uiDrawTextLayout *)tl at:(double)x y:(double)y;
+- (void)returnWidth:(double *)width height:(double *)height;
+- (CFArrayRef)lines;
+@end
+
+@implementation uiprivDrawTextBackgroundParams
+
+- (id)initWithStart:(size_t)s end:(size_t)e r:(double)red g:(double)green b:(double)blue a:(double)alpha
+{
+	self = [super init];
+	if (self) {
+		self->start = s;
+		self->end = e;
+		self->r = red;
+		self->g = green;
+		self->b = blue;
+		self->a = alpha;
+	}
+	return self;
+}
+
+- (void)draw:(CGContextRef)c layout:(uiDrawTextLayout *)layout at:(double)x y:(double)y utf8Mapping:(const size_t *)u16tou8
+{
+	// TODO
+}
+
+@end
+
+@implementation uiprivTextFrame
+
+- (id)initWithLayoutParams:(uiDrawTextLayoutParams *)p
+{
+	CFRange range;
+	CGFloat cgwidth;
+	CFRange unused;
+	CGRect rect;
+
+	self = [super init];
+	if (self) {
+		self->attrstr = uiprivAttributedStringToCFAttributedString(p, &(self->backgroundParams));
+		// TODO kCTParagraphStyleSpecifierMaximumLineSpacing, kCTParagraphStyleSpecifierMinimumLineSpacing, kCTParagraphStyleSpecifierLineSpacingAdjustment for line spacing
+		self->framesetter = CTFramesetterCreateWithAttributedString(self->attrstr);
+		if (self->framesetter == NULL) {
+			// TODO
+		}
+
+		range.location = 0;
+		range.length = CFAttributedStringGetLength(self->attrstr);
+
+		cgwidth = (CGFloat) (p->Width);
+		if (cgwidth < 0)
+			cgwidth = CGFLOAT_MAX;
+		self->size = CTFramesetterSuggestFrameSizeWithConstraints(self->framesetter,
+			range,
+			// TODO kCTFramePathWidthAttributeName?
+			NULL,
+			CGSizeMake(cgwidth, CGFLOAT_MAX),
+			&unused);			// not documented as accepting NULL (TODO really?)
+
+		rect.origin = CGPointZero;
+		rect.size = self->size;
+		self->path = CGPathCreateWithRect(rect, NULL);
+		self->frame = CTFramesetterCreateFrame(self->framesetter,
+			range,
+			self->path,
+			// TODO kCTFramePathWidthAttributeName?
+			NULL);
+		if (self->frame == NULL) {
+			// TODO
+		}
+	}
+	return self;
+}
+
+- (void)dealloc
+{
+	CFRelease(self->frame);
+	CFRelease(self->path);
+	CFRelease(self->framesetter);
+	[self->backgroundParams release];
+	CFRelease(self->attrstr);
+	[super dealloc];
+}
+
+- (void)draw:(uiDrawContext *)c textLayout:(uiDrawTextLayout *)tl at:(double)x y:(double)y
+{
+	uiprivDrawTextBackgroundParams *dtb;
+	CGAffineTransform textMatrix;
+
+	CGContextSaveGState(c->c);
+	// save the text matrix because it's not part of the graphics state
+	textMatrix = CGContextGetTextMatrix(c->c);
+
+	for (dtb in self->backgroundParams)
+		/* TODO */;
+
+	// Core Text doesn't draw onto a flipped view correctly; we have to pretend it was unflipped
+	// see the iOS bits of the first example at https://developer.apple.com/library/mac/documentation/StringsTextFonts/Conceptual/CoreText_Programming/LayoutOperations/LayoutOperations.html#//apple_ref/doc/uid/TP40005533-CH12-SW1 (iOS is naturally flipped)
+	// TODO how is this affected by a non-identity CTM?
+	CGContextTranslateCTM(c->c, 0, c->height);
+	CGContextScaleCTM(c->c, 1.0, -1.0);
+	CGContextSetTextMatrix(c->c, CGAffineTransformIdentity);
+
+	// wait, that's not enough; we need to offset y values to account for our new flipping
+	// TODO explain this calculation
+	y = c->height - self->size.height - y;
+
+	// CTFrameDraw() draws in the path we specified when creating the frame
+	// this means that in our usage, CTFrameDraw() will draw at (0,0)
+	// so move the origin to be at (x,y) instead
+	// TODO are the signs correct?
+	CGContextTranslateCTM(c->c, x, y);
+
+	CTFrameDraw(self->frame, c->c);
+
+	CGContextSetTextMatrix(c->c, textMatrix);
+	CGContextRestoreGState(c->c);
+}
+
+- (void)returnWidth:(double *)width height:(double *)height
+{
+	if (width != NULL)
+		*width = self->size.width;
+	if (height != NULL)
+		*height = self->size.height;
+}
+
+- (CFArrayRef)lines
+{
+	return CTFrameGetLines(self->frame);
+}
+
+@end
+
+struct uiDrawTextLayout {
+	uiprivTextFrame *frame;
+	uiprivTextFrame *forLines;
+	BOOL empty;
+
+	// for converting CFAttributedString indices from/to byte offsets
+	size_t *u8tou16;
+	size_t nUTF8;
+	size_t *u16tou8;
+	size_t nUTF16;
+};
+
+uiDrawTextLayout *uiDrawNewTextLayout(uiDrawTextLayoutParams *p)
+{
+	uiDrawTextLayout *tl;
+
+	tl = uiprivNew(uiDrawTextLayout);
+	tl->frame = [[uiprivTextFrame alloc] initWithLayoutParams:p];
+	if (uiAttributedStringLen(p->String) != 0)
+		tl->forLines = [tl->frame retain];
+	else {
+		uiAttributedString *space;
+		uiDrawTextLayoutParams p2;
+
+		tl->empty = YES;
+		space = uiNewAttributedString(" ");
+		p2 = *p;
+		p2.String = space;
+		tl->forLines = [[uiprivTextFrame alloc] initWithLayoutParams:&p2];
+		uiFreeAttributedString(space);
+	}
+
+	// and finally copy the UTF-8/UTF-16 conversion tables
+	tl->u8tou16 = uiprivAttributedStringCopyUTF8ToUTF16Table(p->String, &(tl->nUTF8));
+	tl->u16tou8 = uiprivAttributedStringCopyUTF16ToUTF8Table(p->String, &(tl->nUTF16));
+	return tl;
+}
+
+void uiDrawFreeTextLayout(uiDrawTextLayout *tl)
+{
+	uiprivFree(tl->u16tou8);
+	uiprivFree(tl->u8tou16);
+	[tl->forLines release];
+	[tl->frame release];
+	uiprivFree(tl);
+}
+
+// TODO document that (x,y) is the top-left corner of the *entire frame*
+void uiDrawText(uiDrawContext *c, uiDrawTextLayout *tl, double x, double y)
+{
+	[tl->frame draw:c textLayout:tl at:x y:y];
+}
+
+// TODO document that the width and height of a layout is not necessarily the sum of the widths and heights of its constituent lines
+// TODO width doesn't include trailing whitespace...
+// TODO figure out how paragraph spacing should play into this
+// TODO standardize and document the behavior of this on an empty layout
+void uiDrawTextLayoutExtents(uiDrawTextLayout *tl, double *width, double *height)
+{
+	// TODO explain this, given the above
+	[tl->frame returnWidth:width height:NULL];
+	[tl->forLines returnWidth:NULL height:height];
+}
+
+void uiLoadControlFont(uiFontDescriptor *f)
+{
+	CTFontRef ctfont;
+	CTFontDescriptorRef ctdesc;
+
+	ctfont = (CTFontRef) [NSFont systemFontOfSize:[NSFont systemFontSizeForControlSize:NSControlSizeRegular]];
+	ctdesc = CTFontCopyFontDescriptor(ctfont);
+	uiprivFontDescriptorFromCTFontDescriptor(ctdesc, f);
+	CFRelease(ctdesc);
+	f->Size = CTFontGetSize(ctfont);
+}
+
+void uiFreeFontDescriptor(uiFontDescriptor *desc)
+{
+	// TODO ensure this is synchronized with fontmatch.m
+	uiFreeText((char *) (desc->Family));
+}