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Issue #932: [GTK] implementation for StyledText.setFixedLineMetrics
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Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
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@SyntevoAlex
SyntevoAlex committed Jan 31, 2024
1 parent 6ae47e8 commit cd799ed
Showing 1 changed file with 175 additions and 18 deletions.
193 changes: 175 additions & 18 deletions bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/TextLayout.java
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Original file line number Diff line number Diff line change
Expand Up @@ -63,8 +63,160 @@ public String toString () {
long layout, context, attrList, selAttrList;
int[] invalidOffsets;
int verticalIndentInPoints;
MetricsAdapter metricsAdapter = new MetricsAdapter();
static final char LTR_MARK = '\u200E', RTL_MARK = '\u200F', ZWS = '\u200B', ZWNBS = '\uFEFF';

/**
* Adapts necessary Pango APIs to enforce fixed line metrics (when set)
*/
private static class MetricsAdapter {
private FontMetrics lineMetricsInPixels;

/**
* Calculates Y offset from line metrics configured in
* {@link #lineMetricsInPixels} to real text position for painting.
*/
private int wantToRealInPango(PangoRectangle realMetrics) {
int wantHeightInPixels = lineMetricsInPixels.getHeight();
int realHeightInPixels = OS.PANGO_PIXELS(realMetrics.height);
if (realHeightInPixels == wantHeightInPixels) {
return 0;
}

// The idea is to preserve baseline location, this looks best.
// This is the behavior documented in `TextLayout#setFixedLineMetrics()`.
int wantAboveInPango = OS.PANGO_SCALE * lineMetricsInPixels.getAscent();
int realAboveInPango = -realMetrics.y;
return wantAboveInPango - realAboveInPango;
}

private int wantToRealInPango(long line) {
PangoRectangle rect = new PangoRectangle();
// Pango caches result, so the API is very cheap to call multiple times
OS.pango_layout_line_get_extents(line, null, rect);
return wantToRealInPango(rect);
}

public boolean isFixedMetrics() {
return (lineMetricsInPixels != null);
}

public FontMetrics getFixedLineMetrics(Device device) {
if (lineMetricsInPixels == null) {
return null;
}

FontMetrics result = new FontMetrics();
result.ascentInPoints = DPIUtil.autoScaleDown(device, lineMetricsInPixels.ascentInPoints);
result.descentInPoints = DPIUtil.autoScaleDown(device, lineMetricsInPixels.descentInPoints);
result.averageCharWidthInPoints = DPIUtil.autoScaleDown(device, lineMetricsInPixels.averageCharWidthInPoints);

return result;
}

public void setFixedLineMetrics(Device device, FontMetrics metrics) {
if (metrics == null) {
lineMetricsInPixels = null;
return;
}

FontMetrics result = new FontMetrics();
result.ascentInPoints = DPIUtil.autoScaleUp(device, metrics.ascentInPoints);
result.descentInPoints = DPIUtil.autoScaleUp(device, metrics.descentInPoints);
result.averageCharWidthInPoints = DPIUtil.autoScaleUp(device, metrics.averageCharWidthInPoints);

lineMetricsInPixels = result;
}

private void validateLayout (long layout) {
// Pango caches result, so the API is very cheap to call multiple times
if (OS.pango_layout_get_line_count(layout) > 1) {
// Multi-line layouts (including word wrapping) are not yet supported.
// Note that `StyledText` uses separate `TextLayout` for every line.
SWT.error (SWT.ERROR_INVALID_ARGUMENT);
}
}

public long gdk_pango_layout_get_clip_region (long layout, int x_origin, int y_origin, int[] index_ranges, int n_ranges) {
// In order to get proper text clip, adjust Y in the same way
// as in pango_cairo_show_layout()
int yAdjustInPixels = 0;
if (isFixedMetrics()) {
validateLayout(layout);
long line0 = OS.pango_layout_get_line(layout, 0);
yAdjustInPixels = OS.PANGO_PIXELS(wantToRealInPango(line0));
}

long rgn = GDK.gdk_pango_layout_get_clip_region(layout, x_origin, y_origin + yAdjustInPixels, index_ranges, n_ranges);

// Adjust region via intersecting with desired region
if (isFixedMetrics()) {
cairo_rectangle_int_t wantRect = new cairo_rectangle_int_t();
// Use real x,width with desired y,height
Cairo.cairo_region_get_extents(rgn, wantRect);
wantRect.y = y_origin;
wantRect.height = lineMetricsInPixels.getHeight();

long limitRgn = Cairo.cairo_region_create_rectangle(wantRect);
Cairo.cairo_region_intersect(rgn, limitRgn);
Cairo.cairo_region_destroy(limitRgn);
}

return rgn;
}

public void pango_cairo_show_layout (long cairo, long layout, double x, double y) {
int yAdjustInPixels = 0;
if (isFixedMetrics()) {
validateLayout(layout);
long line0 = OS.pango_layout_get_line(layout, 0);
yAdjustInPixels = OS.PANGO_PIXELS(wantToRealInPango(line0));
}

Cairo.cairo_move_to(cairo, x, y + yAdjustInPixels);
OS.pango_cairo_show_layout (cairo, layout);
}

public void pango_layout_get_size (long layout, int[] width, int[] height) {
OS.pango_layout_get_size(layout, width, height);

if (isFixedMetrics()) {
validateLayout(layout);
height[0] = lineMetricsInPixels.getHeight();
}
}

public void pango_layout_iter_get_line_extents (long iter, PangoRectangle ink_rect, PangoRectangle logical_rect) {
OS.pango_layout_iter_get_line_extents(iter, ink_rect, logical_rect);

if (isFixedMetrics()) {
if (ink_rect != null) {
// SWT doesn't use that, so I didn't implement
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}

if (logical_rect != null) {
logical_rect.height = OS.PANGO_SCALE * lineMetricsInPixels.getHeight();
}
}
}

public void pango_layout_line_get_extents (long line, PangoRectangle ink_rect, PangoRectangle logical_rect) {
OS.pango_layout_line_get_extents(line, ink_rect, logical_rect);

if (isFixedMetrics()) {
if (ink_rect != null) {
// SWT doesn't use that, so I didn't implement
SWT.error(SWT.ERROR_INVALID_ARGUMENT);
}

if (logical_rect != null) {
logical_rect.height = OS.PANGO_SCALE * lineMetricsInPixels.getHeight();
}
}
}
}

/**
* Constructs a new instance of this class on the given device.
* <p>
Expand Down Expand Up @@ -137,7 +289,12 @@ void computeRuns () {
int nSegments = segementsLength - text.length();
int offsetCount = nSegments;
int[] lineOffsets = null;
if ((ascentInPoints != -1 || descentInPoints != -1) && segementsLength > 0) {

// Set minimum line ascent/descent. Feature in Pango: glyphs affected
// by `pango_attr_shape_new()` become invisible. Workaround: insert
// additional control characters and shape these instead.
boolean useMinAscentDescent = !metricsAdapter.isFixedMetrics() && (ascentInPoints != -1 || descentInPoints != -1);
if (useMinAscentDescent && segementsLength > 0) {
PangoRectangle rect = new PangoRectangle();
if (ascentInPoints != -1) rect.y = -(DPIUtil.autoScaleUp(getDevice(), ascentInPoints) * OS.PANGO_SCALE);
rect.height = DPIUtil.autoScaleUp(getDevice(), (Math.max(0, ascentInPoints) + Math.max(0, descentInPoints))) * OS.PANGO_SCALE;
Expand Down Expand Up @@ -502,7 +659,7 @@ void drawInPixels(GC gc, int x, int y, int selectionStart, int selectionEnd, Col
int lineIndex = 0;
do {
int lineEnd;
OS.pango_layout_iter_get_line_extents(iter, null, rect);
metricsAdapter.pango_layout_iter_get_line_extents(iter, null, rect);
if (OS.pango_layout_iter_next_line(iter)) {
int bytePos = OS.pango_layout_iter_get_index(iter);
lineEnd = (int)OS.g_utf16_pointer_to_offset(ptr, ptr + bytePos);
Expand Down Expand Up @@ -547,8 +704,7 @@ void drawInPixels(GC gc, int x, int y, int selectionStart, int selectionEnd, Col
Cairo.cairo_scale(cairo, -1, 1);
Cairo.cairo_translate(cairo, -2 * x - width(), 0);
}
Cairo.cairo_move_to(cairo, x, y);
OS.pango_cairo_show_layout(cairo, layout);
metricsAdapter.pango_cairo_show_layout(cairo, layout, x, y);
drawBorder(gc, x, y, null);
if ((data.style & SWT.MIRRORED) != 0) {
Cairo.cairo_restore(cairo);
Expand Down Expand Up @@ -601,12 +757,11 @@ void drawWithCairo(GC gc, int x, int y, int start, int end, boolean fullSelectio
long cairo = data.cairo;
Cairo.cairo_save(cairo);
if (!fullSelection) {
Cairo.cairo_move_to(cairo, x, y);
OS.pango_cairo_show_layout(cairo, layout);
metricsAdapter.pango_cairo_show_layout(cairo, layout, x, y);
drawBorder(gc, x, y, null);
}
int[] ranges = new int[]{start, end};
long rgn = GDK.gdk_pango_layout_get_clip_region(layout, x, y, ranges, ranges.length / 2);
long rgn = metricsAdapter.gdk_pango_layout_get_clip_region(layout, x, y, ranges, ranges.length / 2);
if (rgn != 0) {
GDK.gdk_cairo_region(cairo, rgn);
Cairo.cairo_clip(cairo);
Expand All @@ -615,9 +770,8 @@ void drawWithCairo(GC gc, int x, int y, int start, int end, boolean fullSelectio
Cairo.cairo_region_destroy(rgn);
}
Cairo.cairo_set_source_rgba(cairo, fg.red, fg.green, fg.blue, fg.alpha);
Cairo.cairo_move_to(cairo, x, y);
OS.pango_layout_set_attributes(layout, selAttrList);
OS.pango_cairo_show_layout(cairo, layout);
metricsAdapter.pango_cairo_show_layout(cairo, layout, x, y);
OS.pango_layout_set_attributes(layout, attrList);
drawBorder(gc, x, y, fg);
Cairo.cairo_restore(cairo);
Expand All @@ -643,7 +797,7 @@ void drawBorder(GC gc, int x, int y, GdkRGBA selectionColor) {
int byteStart = (int)(OS.g_utf16_offset_to_pointer(ptr, start) - ptr);
int byteEnd = (int)(OS.g_utf16_offset_to_pointer(ptr, end + 1) - ptr);
int[] ranges = new int[]{byteStart, byteEnd};
long rgn = GDK.gdk_pango_layout_get_clip_region(layout, x, y, ranges, ranges.length / 2);
long rgn = metricsAdapter.gdk_pango_layout_get_clip_region(layout, x, y, ranges, ranges.length / 2);
if (rgn != 0) {
int[] nRects = new int[1];
long [] rects = new long [1];
Expand Down Expand Up @@ -761,7 +915,7 @@ Rectangle getBoundsInPixels(int spacingInPixels) {
checkLayout();
computeRuns();
int[] w = new int[1], h = new int[1];
OS.pango_layout_get_size(layout, w, h);
metricsAdapter.pango_layout_get_size(layout, w, h);
int wrapWidth = OS.pango_layout_get_width(layout);
w[0] = wrapWidth != -1 ? wrapWidth : w[0] + OS.pango_layout_get_indent(layout);
int width = OS.PANGO_PIXELS(w[0]);
Expand Down Expand Up @@ -809,7 +963,7 @@ Rectangle getBoundsInPixels(int start, int end) {
byteStart = Math.min(byteStart, strlen);
byteEnd = Math.min(byteEnd, strlen);
int[] ranges = new int[]{byteStart, byteEnd};
long clipRegion = GDK.gdk_pango_layout_get_clip_region(layout, 0, 0, ranges, 1);
long clipRegion = metricsAdapter.gdk_pango_layout_get_clip_region(layout, 0, 0, ranges, 1);
if (clipRegion == 0) return new Rectangle(0, 0, 0, 0);
cairo_rectangle_int_t rect = new cairo_rectangle_int_t();

Expand All @@ -825,7 +979,7 @@ Rectangle getBoundsInPixels(int start, int end) {
if (linesRegion == 0) SWT.error(SWT.ERROR_NO_HANDLES);
int lineEnd = 0;
do {
OS.pango_layout_iter_get_line_extents(iter, null, pangoRect);
metricsAdapter.pango_layout_iter_get_line_extents(iter, null, pangoRect);
if (OS.pango_layout_iter_next_line(iter)) {
lineEnd = OS.pango_layout_iter_get_index(iter) - 1;
} else {
Expand Down Expand Up @@ -996,7 +1150,7 @@ Rectangle getLineBoundsInPixels(int lineIndex) {
private Rectangle getLineBoundsInPixels(int lineIndex, long iter) {
if (iter == 0) SWT.error(SWT.ERROR_NO_HANDLES);
PangoRectangle rect = new PangoRectangle();
OS.pango_layout_iter_get_line_extents(iter, null, rect);
metricsAdapter.pango_layout_iter_get_line_extents(iter, null, rect);
int x = OS.PANGO_PIXELS(rect.x);
int y = OS.PANGO_PIXELS(rect.y);
int width = OS.PANGO_PIXELS(rect.width);
Expand Down Expand Up @@ -1073,6 +1227,10 @@ public int getLineIndex(int offset) {
* </ul>
*/
public FontMetrics getLineMetrics (int lineIndex) {
if (metricsAdapter.isFixedMetrics()) {
return metricsAdapter.getFixedLineMetrics(getDevice());
}

checkLayout ();
computeRuns();
int lineCount = OS.pango_layout_get_line_count(layout);
Expand All @@ -1092,7 +1250,7 @@ public FontMetrics getLineMetrics (int lineIndex) {
OS.pango_font_metrics_unref(metrics);
} else {
PangoRectangle rect = new PangoRectangle();
OS.pango_layout_line_get_extents(OS.pango_layout_get_line(layout, lineIndex), null, rect);
metricsAdapter.pango_layout_line_get_extents(OS.pango_layout_get_line(layout, lineIndex), null, rect);
ascentInPoints = DPIUtil.autoScaleDown(getDevice(), OS.PANGO_PIXELS(-rect.y));
heightInPoints = DPIUtil.autoScaleDown(getDevice(), OS.PANGO_PIXELS(rect.height));
}
Expand Down Expand Up @@ -1346,7 +1504,7 @@ int getOffsetInPixels(int x, int y, int[] trailing) {
if (iter == 0) SWT.error(SWT.ERROR_NO_HANDLES);
PangoRectangle rect = new PangoRectangle();
do {
OS.pango_layout_iter_get_line_extents(iter, null, rect);
metricsAdapter.pango_layout_iter_get_line_extents(iter, null, rect);
rect.y = OS.PANGO_PIXELS(rect.y);
rect.height = OS.PANGO_PIXELS(rect.height);
if (rect.y <= y && y < rect.y + rect.height) {
Expand Down Expand Up @@ -1828,8 +1986,7 @@ public void setDescent (int descent) {
* @since 3.125
*/
public void setFixedLineMetrics (FontMetrics metrics) {
if (metrics == null) return;
SWT.error(SWT.ERROR_NOT_IMPLEMENTED);
metricsAdapter.setFixedLineMetrics(getDevice(), metrics);
}

/**
Expand Down

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