Add support for arbitrarily transformed Windows buttons text fields, and select boxes (but does not affect scroll bars). I created a helper class, ThemeHelperWin, which automatically wraps the logic necessary to do this. There are three modes: draw the form control normally, draw it at a different size (for scaling, just tell Windows it's a different size and don't transform the graphics coordinates), or arbitrary transforms (where it's drawn to an offscreen buffer and transformed by our graphics layer.

Review URL: http://codereview.chromium.org/9008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@4890 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 264 insertions, 25 deletions

diff --git a/webkit/build/port/port.vcproj b/webkit/build/port/port.vcproj
index 7464c87..b18530a 100644
--- a/webkit/build/port/port.vcproj
+++ b/webkit/build/port/port.vcproj
@@ -974,6 +974,14 @@
 					RelativePath="..\..\port\platform\graphics\SkiaUtils.h"
 					>
 				</File>
+				<File
+					RelativePath="..\..\port\platform\graphics\ThemeHelperWin.cpp"
+					>
+				</File>
+				<File
+					RelativePath="..\..\port\platform\graphics\ThemeHelperWin.h"
+					>
+				</File>
 				<Filter
 					Name="svg"
 					>
diff --git a/webkit/port/platform/graphics/ThemeHelperWin.cpp b/webkit/port/platform/graphics/ThemeHelperWin.cpp
new file mode 100644
index 0000000..10916e6
--- /dev/null
+++ b/webkit/port/platform/graphics/ThemeHelperWin.cpp
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2008 Google Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "FloatRect.h"
+#include "GraphicsContext.h"
+#include "ThemeHelperWin.h"
+
+namespace WebCore {
+
+static void IntRectToRECT(const IntRect& ir, RECT* r)
+{
+    r->left = ir.x();
+    r->top = ir.y();
+    r->right = ir.right();
+    r->bottom = ir.bottom();
+}
+
+ThemeHelperWin::ThemeHelperWin(GraphicsContext* context,
+                               const IntRect& rect)
+    : m_orgContext(context)
+    , m_orgMatrix(context->getCTM())
+    , m_orgRect(rect)
+{
+    if (m_orgMatrix.b() != 0 ||  // Y skew
+        m_orgMatrix.c() != 0) {  // X skew
+        // Complicated effects, make a copy and draw the bitmap there.
+        m_type = COPY;
+        m_rect.left = 0;
+        m_rect.top = 0;
+        m_rect.right = rect.width();
+        m_rect.bottom = rect.height();
+
+        m_newBuffer.set(ImageBuffer::create(rect.size(), false).release());
+
+        // Theme drawing messes with the transparency.
+        // TODO(brettw) Ideally, we would leave this transparent, but I was
+        // having problems with button drawing, so we fill with white. Buttons
+        // looked good with transparent here and no fixing up of the alpha
+        // later, but text areas didn't. This makes text areas look good but
+        // gives buttons a white halo. Is there a way to fix this? I think
+        // buttons actually have antialised edges which is just not possible
+        // to handle on a transparent background given that it messes with the
+        // alpha channel.
+        FloatRect newContextRect(0, 0, rect.width(), rect.height());
+        GraphicsContext* newContext = m_newBuffer->context();
+        newContext->setFillColor(Color::white);
+        newContext->fillRect(newContextRect);
+
+        return;
+    }
+
+    if (m_orgMatrix.a() != 1.0 ||  // X scale
+        m_orgMatrix.d() != 1.0) {  // Y scale
+        // Only a scaling is applied.
+        m_type = SCALE;
+
+        // Save the transformed coordinates to draw.
+        IntRectToRECT(m_orgMatrix.mapRect(rect), &m_rect);
+        
+        m_orgContext->save();
+        m_orgContext->concatCTM(m_orgContext->getCTM().inverse());
+        return;
+    }
+
+    // Nothing interesting.
+    IntRectToRECT(rect, &m_rect);
+    m_type = ORIGINAL;
+}
+
+ThemeHelperWin::~ThemeHelperWin()
+{
+    switch (m_type) {
+    case SCALE:
+        m_orgContext->restore();
+        break;
+    case COPY: {
+        // Copy the duplicate bitmap with our control to the original canvas.
+        FloatRect destRect(m_orgRect);
+        m_newBuffer->context()->platformContext()->canvas()->
+            getTopPlatformDevice().fixupAlphaBeforeCompositing();
+        m_orgContext->drawImage(m_newBuffer->image(), destRect);
+        break;
+    }
+    case ORIGINAL:
+        break;
+    }
+}
+
+RECT ThemeHelperWin::transformRect(const RECT& r) const
+{
+    IntRect src(r.left, r.top, r.right - r.left, r.bottom - r.top);
+    IntRect dest;
+    switch (m_type) {
+    case SCALE:
+        dest = m_orgMatrix.mapRect(src);
+        break;
+    case COPY:
+        dest = src;
+        dest.move(-m_orgRect.x(), -m_orgRect.y());
+        break;
+    case ORIGINAL:
+        break;
+    }
+
+    RECT output;
+    IntRectToRECT(dest, &output);
+    return output;
+}
+
+}  // namespace WebCore
\ No newline at end of file
diff --git a/webkit/port/platform/graphics/ThemeHelperWin.h b/webkit/port/platform/graphics/ThemeHelperWin.h
new file mode 100644
index 0000000..3d7caf1
--- /dev/null
+++ b/webkit/port/platform/graphics/ThemeHelperWin.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2008 Google Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef ThemeHelperWin_h
+#define ThemeHelperWin_h
+
+#include <windows.h>
+
+#include "AffineTransform.h"
+#include "ImageBuffer.h"
+#include "IntRect.h"
+#include "WTF/OwnPtr.h"
+
+namespace WebCore {
+
+class GraphicsContext;
+class IntRect;
+
+// Helps drawing theme elements like buttons and scroll bars. This will handle
+// translations and scalings that Windows might not, by either making Windows
+// draw the appropriate sized control, or by rendering it into an off-screen
+// context and transforming it ourselves.
+class ThemeHelperWin {
+    enum Type {
+        // Use the original canvas with no changes. This is the normal mode.
+        ORIGINAL,
+
+        // Use the original canvas but scale the rectangle of the control so
+        // that it will be the correct size, undoing any scale already on the
+        // canvas. This will have the effect of just drawing the control bigger
+        // or smaller and not actually expanding or contracting the pixels in
+        // it. This usually looks better.
+        SCALE,
+
+        // Make a copy of the control and then transform it ourselves after
+        // Windows draws it. This allows us to get complex effects.
+        COPY,
+    };
+
+public:
+    // Prepares drawing a control with the given rect to the given context.
+    ThemeHelperWin(GraphicsContext* context, const IntRect& rect);
+    ~ThemeHelperWin();
+
+    // Returns the context to draw the control into, which may be the original
+    // or the copy, depending on the mode.
+    GraphicsContext* context()
+    {
+        return m_newBuffer.get() ? m_newBuffer->context() : m_orgContext;
+    }
+
+    // Returns the rectangle in which to draw into the canvas() by Windows.
+    const RECT& rect() { return m_rect; }
+
+    RECT transformRect(const RECT& r) const;
+
+private:
+    Type m_type;
+
+    // The original canvas to wrote to. Not owned by this class.
+    GraphicsContext* m_orgContext;
+    AffineTransform m_orgMatrix;
+    IntRect m_orgRect;
+
+    // When m_type == COPY, this will be a new surface owned by this class that
+    // represents the copy.
+    OwnPtr<ImageBuffer> m_newBuffer;
+
+    // The control rectangle in the cooredinate space of canvas().
+    RECT m_rect;
+};
+
+}  // namespace WebCore
+
+#endif  // ThemeHelperWin_h
diff --git a/webkit/port/rendering/RenderThemeWin.cpp b/webkit/port/rendering/RenderThemeWin.cpp
index 2bb81ab..917e5ee 100644
--- a/webkit/port/rendering/RenderThemeWin.cpp
+++ b/webkit/port/rendering/RenderThemeWin.cpp
@@ -33,6 +33,7 @@
 #include "GraphicsContext.h"
 #include "ScrollbarTheme.h"
 #include "SkiaUtils.h"
+#include "ThemeHelperWin.h"
 
 #include "base/gfx/native_theme.h"
 #include "base/gfx/font_utils.h"
@@ -482,20 +483,19 @@ bool RenderThemeWin::paintButton(RenderObject* o,
 {
     const ThemeData& themeData = getThemeData(o);
 
-    RECT rect;
-    rect.left = r.x();
-    rect.top = r.y();
-    rect.right = r.right();
-    rect.bottom = r.bottom();
+    WebCore::ThemeHelperWin helper(i.context, r);
+    gfx::PlatformCanvas* canvas = helper.context()->platformContext()->canvas();
 
-    HDC hdc = i.context->platformContext()->canvas()->beginPlatformPaint();
+    HDC hdc = canvas->beginPlatformPaint();
     int state = themeData.m_state;
+    RECT renderRect = helper.rect();
+
     gfx::NativeTheme::instance()->PaintButton(hdc,
                                               themeData.m_part,
                                               state,
                                               themeData.m_classicState,
-                                              &rect);
-    i.context->platformContext()->canvas()->endPlatformPaint();
+                                              &renderRect);
+    canvas->endPlatformPaint();
     return false;
 }
 
@@ -574,23 +574,22 @@ bool RenderThemeWin::paintTextFieldInternal(RenderObject* o,
 
     const ThemeData& themeData = getThemeData(o);
 
-    RECT rect;
-    rect.left = r.x();
-    rect.top = r.y();
-    rect.right = r.right();
-    rect.bottom = r.bottom();
+    WebCore::ThemeHelperWin helper(i.context, r);
+    gfx::PlatformCanvas* canvas = helper.context()->platformContext()->canvas();
 
-    HDC hdc = i.context->platformContext()->canvas()->beginPlatformPaint();
+    HDC hdc = canvas->beginPlatformPaint();
     COLORREF clr = gfx::SkColorToCOLORREF(o->style()->backgroundColor().rgb());
+    RECT renderRect = helper.rect();
+
     gfx::NativeTheme::instance()->PaintTextField(hdc,
                                                  themeData.m_part,
                                                  themeData.m_state,
                                                  themeData.m_classicState,
-                                                 &rect,
+                                                 &renderRect,
                                                  clr,
                                                  true,
                                                  drawEdges);
-    i.context->platformContext()->canvas()->endPlatformPaint();
+    canvas->endPlatformPaint();
     return false;
 }
 
@@ -662,21 +661,23 @@ bool RenderThemeWin::paintMenuList(RenderObject* o, const RenderObject::PaintInf
         buttonX = o->style()->direction() == LTR ? r.right() - spacingRight - buttonWidth : r.x() + spacingLeft;
     }
 
-    // Compute the Windows rectangle of the button.
-    RECT rect;
-    rect.left = buttonX;
-    rect.top = r.y() + spacingTop;
-    rect.right = rect.left + std::min(buttonWidth, r.right() - r.x());
-    rect.bottom = rect.top + r.height() - (spacingTop + spacingBottom);
+    // Compute the rectangle of the button in the destination image.
+    IntRect rect(buttonX,
+                 r.y() + spacingTop,
+                 std::min(buttonWidth, r.right() - r.x()),
+                 r.height() - (spacingTop + spacingBottom));
 
     // Get the correct theme data for a textfield and paint the menu.
-    HDC hdc = i.context->platformContext()->canvas()->beginPlatformPaint();
+    WebCore::ThemeHelperWin helper(i.context, rect);
+    gfx::PlatformCanvas* canvas = helper.context()->platformContext()->canvas();
+    HDC hdc = canvas->beginPlatformPaint();
+    RECT renderRect = helper.rect();
     gfx::NativeTheme::instance()->PaintMenuList(hdc,
                                                 CP_DROPDOWNBUTTON,
                                                 determineState(o),
                                                 determineClassicState(o),
-                                                &rect);
-    i.context->platformContext()->canvas()->endPlatformPaint();
+                                                &renderRect);
+    canvas->endPlatformPaint();
     return false;
 }