GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing #2526

arunjose696 · 2025-09-19T12:52:04Z

The DrawImage API with just destination coordinates now tries to load images at the requested size.
If the requested size is not available, it falls back to the closest available size by calculating the appropriate zoom.
Images are loadable at the target size if the image is created from an SVG stream or filename, or The image is created with an ImageDataProvider that is ImageDataAtSizeProvider.

This commit also introduces the ImageDataAtSizeProvider interface to support dynamic sizing.

With this changes we need to test the following

The svgs are rendered at custom sizes without blurry scaling (this can be compared with current commit vs master)
Drawing images with targetHeight and targetWidth with ImageDataAtSizeProvider (comparison can be made against ImageDataProvider vs ImageDataAtSizeProvider both at this commit)
Steps to reproduce:

snippet 1 to check drawing svgs at custom sizes (click to show snippet)

**Step 1**: Copy the eclipse.svg to same path where the snippets are and run the below snippet. **Step 2**: Run the snippet

package org.eclipse.swt.snippets;

package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet386 {

    public static void main(String[] args) {
        Display display = new Display();

        Image[] images = new Image[] {

            new Image(display, createImageFileNameProvider("src/org/eclipse/swt/snippets/eclipse.svg")),

        };

        String[] descriptions = new String[] {

            "ImageFileNameProvider with SVGs scaled by SVG rasterization"
        };

        Slice[] slices = {
        		 new Slice("Full", 0.0, 0.0, 1.0, 1.0),
                 new Slice("Top Half", 0.0, 0.0, 1.0, 0.5)
        };

        createShellWithImages(display, images, descriptions, slices, "Snippet 386 - Flipped Layout");
    }

    private static ImageFileNameProvider createImageFileNameProvider(String fileName) {
        return zoom -> {
        	if(zoom==100)
        	return fileName;
        	return null;};
    }

    static class Slice {
        String name;
        double xFrac, yFrac, wFrac, hFrac;
        Slice(String name, double x, double y, double w, double h) {
            this.name = name;
            this.xFrac = x;
            this.yFrac = y;
            this.wFrac = w;
            this.hFrac = h;
        }
    }

    private static void createShellWithImages(Display display, Image[] images, String[] descriptions, Slice[] slices, String title) {
        Shell shell = new Shell(display, SWT.SHELL_TRIM | SWT.MAX | SWT.RESIZE);
        shell.setText(title);
        shell.setLayout(new FillLayout());

        ScrolledComposite scrolledComposite = new ScrolledComposite(shell, SWT.V_SCROLL | SWT.H_SCROLL | SWT.BORDER);
        Canvas canvas = new Canvas(scrolledComposite, SWT.DOUBLE_BUFFERED);
        scrolledComposite.setContent(canvas);
        scrolledComposite.setExpandHorizontal(true);
        scrolledComposite.setExpandVertical(true);

        int boxW = 1500, boxH = 1500, gap = 20;
        int titleHeight = 20, descHeight = 40, sliceHeaderHeight = 30;

        int rows = images.length;
        int cols = slices.length;

        int canvasWidth = (boxW + gap) * cols + gap;
        int canvasHeight = (boxH + titleHeight + gap) * rows + descHeight + sliceHeaderHeight;
        canvas.setSize(canvasWidth, canvasHeight);
        scrolledComposite.setMinSize(canvasWidth, canvasHeight);

        canvas.addListener(SWT.Paint, e -> {
            // Column headers
            for (int col = 0; col < cols; col++) {
                int x = col * (boxW + gap) + gap;
                Font font = new Font(display, "Arial", 18, SWT.NORMAL);
                e.gc.setFont(font);
                e.gc.drawText(slices[col].name, x, 0, true);
                font.dispose();

            }

            // Rows
            for (int row = 0; row < rows; row++) {
                Image image = images[row];
                Rectangle rect = image.getBounds();
                int y = row * (boxH + titleHeight + gap) + descHeight + sliceHeaderHeight;

                Font font = new Font(display, "Arial", 18, SWT.NORMAL);
                e.gc.setFont(font);
                e.gc.drawText(descriptions[row], 0, y - 10, true);
                font.dispose();

                for (int col = 0; col < cols; col++) {
                    Slice s = slices[col];
                    int x = col * (boxW + gap) + gap;

                    int boxTop = y + titleHeight;
                    e.gc.drawRectangle(x, boxTop, (int) Math.round(boxW / s.wFrac), (int) Math.round(boxH / s.hFrac));

                    e.gc.drawImage(image, x, boxTop, (int) Math.round(boxW / s.wFrac), (int) Math.round(boxH / s.hFrac));
                }
            }
        });

        shell.setMaximized(true);
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) display.sleep();
        }

        for (Image img : images) img.dispose();
        display.dispose();
    }
}

_before
_after

**snippet 2** Drawing images with ImageDataAtSizeProvider

package org.eclipse.swt.snippets;

package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet386 {

    public static void main(String[] args) {
        Display display = new Display();

        Image[] images = new Image[] {
            new Image(display, createImageDataProvider()),
            new Image(display, createImageDataAtSizeProvider())
        };

        String[] descriptions = new String[] {

            "ImageDataProvider with fixed font size for a given zoom",
            "ImageDataAtSizeProvider which scales font size based on target height and width"
        };

        Slice[] slices = {
            new Slice("Full", 0.0, 0.0, 1.0, 1.0),
   
        };

        createShellWithImages(display, images, descriptions, slices, "Snippet 386 - Flipped Layout");
    }



    private static ImageDataProvider createImageDataProvider() {
        return new ImageDataProvider() {
            @Override
            public ImageData getImageData(int zoomLevel) {
                int scaleFactor = zoomLevel / 100;
                return createScaledTextImageData(100 * scaleFactor, 100 * scaleFactor);
            }
        };
    }

    private static ImageDataProvider createImageDataAtSizeProvider() {
        return new ImageDataAtSizeProvider() {
            @Override
            public ImageData getImageData(int zoomLevel) {
                int scaleFactor = zoomLevel / 100;
                return createScaledTextImageData(100 * scaleFactor, 100 * scaleFactor);
            }

            @Override
            public ImageData getImageData(int width, int height) {
                return createScaledTextImageData(width, height);
            }
        };
    }

    private static ImageData createScaledTextImageData(int width, int height) {
        Display display = Display.getDefault();
        String text = "abcd";

        int fontSize = Math.max(1, height / 100);
        Font font = new Font(display, "Arial", fontSize, SWT.NORMAL);

        Image tmp = new Image(display, 1, 1);
        GC measureGC = new GC(tmp);
        measureGC.setFont(font);
        Point textExtent = measureGC.textExtent(text);
        measureGC.dispose();
        tmp.dispose();

        double scale = Math.min((double) width / textExtent.x, (double) height / textExtent.y);
        font.dispose();
        font = new Font(display, "Arial", Math.max(1, (int) (fontSize * scale)), SWT.NORMAL);

        Image image = new Image(display, width, height);
        GC gc = new GC(image);
        gc.setFont(font);
        gc.setForeground(display.getSystemColor(SWT.COLOR_BLACK));
        gc.setBackground(display.getSystemColor(SWT.COLOR_WHITE));
        gc.fillRectangle(image.getBounds());

        gc.setLineWidth(Math.max(1, width / 20));
        gc.drawLine(0, 0, width / 2, height);

        Point newTextExtent = gc.textExtent(text);
        gc.drawText(text, (width - newTextExtent.x) / 2, (height - newTextExtent.y) / 2, true);

        gc.dispose();
        ImageData data = image.getImageData();

        image.dispose();
        font.dispose();

        return data;
    }

    static class Slice {
        String name;
        double xFrac, yFrac, wFrac, hFrac;
        Slice(String name, double x, double y, double w, double h) {
            this.name = name;
            this.xFrac = x;
            this.yFrac = y;
            this.wFrac = w;
            this.hFrac = h;
        }
    }

    private static void createShellWithImages(Display display, Image[] images, String[] descriptions, Slice[] slices, String title) {
        Shell shell = new Shell(display, SWT.SHELL_TRIM | SWT.MAX | SWT.RESIZE);
        shell.setText(title);
        shell.setLayout(new FillLayout());

        ScrolledComposite scrolledComposite = new ScrolledComposite(shell, SWT.V_SCROLL | SWT.H_SCROLL | SWT.BORDER);
        Canvas canvas = new Canvas(scrolledComposite, SWT.DOUBLE_BUFFERED);
        scrolledComposite.setContent(canvas);
        scrolledComposite.setExpandHorizontal(true);
        scrolledComposite.setExpandVertical(true);

        int boxW = 500, boxH = 500, gap = 20;
        int titleHeight = 20, descHeight = 40, sliceHeaderHeight = 30;

        int rows = images.length;
        int cols = slices.length;

        int canvasWidth = (boxW + gap) * cols + gap;
        int canvasHeight = (boxH + titleHeight + gap) * rows + descHeight + sliceHeaderHeight;
        canvas.setSize(canvasWidth, canvasHeight);
        scrolledComposite.setMinSize(canvasWidth, canvasHeight);

        canvas.addListener(SWT.Paint, e -> {
            // Column headers
            for (int col = 0; col < cols; col++) {
                int x = col * (boxW + gap) + gap;
                Font font = new Font(display, "Arial", 18, SWT.NORMAL);
                e.gc.setFont(font);
                e.gc.drawText(slices[col].name, x, 0, true);
                font.dispose();

            }

            // Rows
            for (int row = 0; row < rows; row++) {
                Image image = images[row];
                Rectangle rect = image.getBounds();
                int y = row * (boxH + titleHeight + gap) + descHeight + sliceHeaderHeight;

                Font font = new Font(display, "Arial", 18, SWT.NORMAL);
                e.gc.setFont(font);
                e.gc.drawText(descriptions[row], 0, y - 10, true);
                font.dispose();

                for (int col = 0; col < cols; col++) {
                    Slice s = slices[col];
                    int x = col * (boxW + gap) + gap;

                    int srcX = (int) (rect.width * s.xFrac);
                    int srcY = (int) (rect.height * s.yFrac);
                    int srcW = (int) (rect.width * s.wFrac);
                    int srcH = (int) (rect.height * s.hFrac);

                    int boxTop = y + titleHeight;
                    e.gc.drawRectangle(x, boxTop, boxW, boxH);


                    e.gc.drawImage(image, x, boxTop, boxW, boxH);

                }
            }
        });

        shell.setMaximized(true);
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) display.sleep();
        }

        for (Image img : images) img.dispose();
        display.dispose();
    }
}

This depends on #2514 and #2509, Only last commit is relevant to this PR

github-actions · 2025-09-19T13:02:16Z

Test Results

118 files ±0 118 suites ±0 12m 4s ⏱️ +59s
4 583 tests ±0 4 547 ✅ ±0 36 💤 ±0 0 ❌ ±0
330 runs ±0 307 ✅ ±0 23 💤 ±0 0 ❌ ±0

Results for commit b238dec. ± Comparison against base commit 749ed1a.

♻️ This comment has been updated with latest results.

HeikoKlare

I scanned the PR and commented on some obvious or essential points I came across.

bundles/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/internal/image/FileFormat.java

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/GC.java

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java

HeikoKlare

Thank you for the latest cleanups. They made the code much easier to understand.
Reading the code again I see that, if I am not mistaken, it breaks the existing (implicit) contract for the cache image data, such that it would like lead to a regression. That's why I request changes to avoid that we break existing behavior,
In addition, all the changes related to creating a temporary handle based on zoom for executing a drawing operation on look far more complicated than they need to be to me. I wrote a longer comment trying to explain what in my opinion can/should be done to improve that.

...les/org.eclipse.swt/Eclipse SWT/common/org/eclipse/swt/graphics/ImageDataAtSizeProvider.java

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/Image.java

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java

akoch-yatta

Changes look good to me and I didn't find any regression testing it with the Runtime or the CustomControlExample that already use the new GC API that triggers the changed logic

…en possible. The DrawImage API with just destination coordinates now tries to load images at the requested size. If the requested size is not available, it falls back to the closest available size by calculating the appropriate zoom. Images are loadable at the target size if the image is created from an SVG stream or filename, or The image is created with an ImageDataProvider that is ImageDataAtSizeProvider. This commit also introduces the ImageDataAtSizeProvider interface to support dynamic sizing. Co-authored-by: Michael Bangas <michael.bangas@vector.com>

This commit reverts the changes introduced in eclipse-platform#2526 where getImageData and getScaledImageData were mistakenly interchanged. The initial approach aimed to use this method in loadImageDataClosestTo when images couldn't be loaded at the exact size. However, the final implementation used loadImageData(zoom) instead, making those changes unnecessary. These leftover modifications were an unintended side effect, and this commit removes them.

This commit reverts the changes introduced in #2526 where getImageData and getScaledImageData were mistakenly interchanged. The initial approach aimed to use this method in loadImageDataClosestTo when images couldn't be loaded at the exact size. However, the final implementation used loadImageData(zoom) instead, making those changes unnecessary. These leftover modifications were an unintended side effect, and this commit removes them.

This commit reverts the changes introduced in eclipse-platform#2526 where getImageData and getScaledImageData were mistakenly interchanged. The initial approach aimed to use this method in loadImageDataClosestTo when images couldn't be loaded at the exact size. However, the final implementation used loadImageData(zoom) instead, making those changes unnecessary. These leftover modifications were an unintended side effect, and this commit removes them.

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 7 times, most recently from 01766e0 to fa4a774 Compare September 22, 2025 12:44

arunjose696 mentioned this pull request Sep 22, 2025

Extend ImageLoader to be able to load images at a given height and width #2509

Merged

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 3 times, most recently from 8cf1bfb to 063d70b Compare September 23, 2025 07:59

arunjose696 linked an issue Sep 24, 2025 that may be closed by this pull request

Extend ImageLoader to able to load images at a given target height and width vi-eclipse/Eclipse-Platform#454

Closed

arunjose696 removed a link to an issue Sep 24, 2025

Extend ImageLoader to able to load images at a given target height and width vi-eclipse/Eclipse-Platform#454

Closed

arunjose696 mentioned this pull request Sep 24, 2025

Adding DynamicallySizableImageDataProvider which enables loading images at custom sizes vi-eclipse/Eclipse-Platform#455

Closed

arunjose696 linked an issue Sep 24, 2025 that may be closed by this pull request

Adding DynamicallySizableImageDataProvider which enables loading images at custom sizes vi-eclipse/Eclipse-Platform#455

Closed

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch from 063d70b to a9b9404 Compare September 24, 2025 15:22

arunjose696 marked this pull request as ready for review September 25, 2025 09:35

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 4 times, most recently from 82c03f5 to daf247e Compare September 26, 2025 14:35

HeikoKlare reviewed Sep 26, 2025

View reviewed changes

HeikoKlare reviewed Sep 28, 2025

View reviewed changes

bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java Outdated Show resolved Hide resolved

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 3 times, most recently from e7af9a1 to d25c48a Compare September 29, 2025 17:12

HeikoKlare reviewed Sep 29, 2025

View reviewed changes

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 2 times, most recently from 0e9ab55 to d3575ff Compare September 30, 2025 08:20

HeikoKlare requested changes Sep 30, 2025

View reviewed changes

arunjose696 mentioned this pull request Oct 1, 2025

Adding loadImageData(zoom) to the AbstractImageProvider Wrapper #2570

Merged

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 3 times, most recently from 30de03f to fe7048d Compare October 1, 2025 15:15

arunjose696 requested a review from HeikoKlare October 1, 2025 15:16

arunjose696 force-pushed the arunjose696/326/imageAtSizeProvider branch 4 times, most recently from 3875d39 to d07939a Compare October 1, 2025 16:15

akoch-yatta approved these changes Oct 1, 2025

View reviewed changes

akoch-yatta force-pushed the arunjose696/326/imageAtSizeProvider branch from d07939a to db2d773 Compare October 1, 2025 16:55

HeikoKlare approved these changes Oct 1, 2025

View reviewed changes

akoch-yatta force-pushed the arunjose696/326/imageAtSizeProvider branch 2 times, most recently from 8c1661a to 627d661 Compare October 1, 2025 17:00

HeikoKlare force-pushed the arunjose696/326/imageAtSizeProvider branch from 627d661 to b238dec Compare October 1, 2025 18:39

akoch-yatta merged commit 7a53f1b into eclipse-platform:master Oct 1, 2025
17 checks passed

This was referenced Oct 2, 2025

Extend ImageDataAtSizeProvider support to MacOS vi-eclipse/Eclipse-Platform#466

Closed

Extend ImageDataAtSizeProvider support to Linux vi-eclipse/Eclipse-Platform#467

Closed

akoch-yatta deleted the arunjose696/326/imageAtSizeProvider branch October 2, 2025 07:27

HeikoKlare mentioned this pull request Oct 2, 2025

Extend ImageDataAtSizeProvider to cropped image rendering vi-eclipse/Eclipse-Platform#468

Open

This was referenced Oct 15, 2025

Reuse existing handles when drawing image at size vi-eclipse/Eclipse-Platform#479

Closed

[MacOS] Support loading and drawing images at desired size #2619

Merged

StackOverflowError in ExistingImageHandleProviderWrapper vi-eclipse/Eclipse-Platform#481

Closed

arunjose696 mentioned this pull request Oct 17, 2025

Reverting a side effect introduced in #2526 #2647

Merged

arunjose696 mentioned this pull request Oct 17, 2025

[GTK] Support loading and drawing images at desired size #2622

Merged

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing #2526

GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing #2526

Uh oh!

arunjose696 commented Sep 19, 2025 •

edited

Loading

Uh oh!

github-actions bot commented Sep 19, 2025 •

edited

Loading

Uh oh!

HeikoKlare left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

HeikoKlare left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

akoch-yatta left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing #2526

GC#DrawImage(image, destX, destY, destWidth, destHeight) now tries to load images at the requested destination size before drawing #2526

Uh oh!

Conversation

arunjose696 commented Sep 19, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Sep 19, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Test Results

Uh oh!

HeikoKlare left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

HeikoKlare left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

akoch-yatta left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

arunjose696 commented Sep 19, 2025 •

edited

Loading

github-actions bot commented Sep 19, 2025 •

edited

Loading