LibDraw: Introduce (formerly known as SharedGraphics.)

Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.

This avoids building the code twice, and will encourage better separation
of concerns. :^)

Libraries/LibDraw/Painter.cpp

@@ -0,0 +1,808 @@
+#include "Painter.h"
+#include "Font.h"
+#include "GraphicsBitmap.h"
+#include <AK/Assertions.h>
+#include <AK/StdLibExtras.h>
+#include <AK/StringBuilder.h>
+#include <LibDraw/CharacterBitmap.h>
+#include <math.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#pragma GCC optimize("O3")
+
+template<GraphicsBitmap::Format format = GraphicsBitmap::Format::Invalid>
+static ALWAYS_INLINE Color get_pixel(const GraphicsBitmap& bitmap, int x, int y)
+{
+    if constexpr (format == GraphicsBitmap::Format::Indexed8)
+        return bitmap.palette_color(bitmap.bits(y)[x]);
+    if constexpr (format == GraphicsBitmap::Format::RGB32)
+        return Color::from_rgb(bitmap.scanline(y)[x]);
+    if constexpr (format == GraphicsBitmap::Format::RGBA32)
+        return Color::from_rgba(bitmap.scanline(y)[x]);
+    return bitmap.get_pixel(x, y);
+}
+
+Painter::Painter(GraphicsBitmap& bitmap)
+    : m_target(bitmap)
+{
+    m_state_stack.append(State());
+    state().font = &Font::default_font();
+    state().clip_rect = { { 0, 0 }, bitmap.size() };
+    m_clip_origin = state().clip_rect;
+}
+
+Painter::~Painter()
+{
+}
+
+void Painter::fill_rect_with_draw_op(const Rect& a_rect, Color color)
+{
+    auto rect = a_rect.translated(translation()).intersected(clip_rect());
+    if (rect.is_empty())
+        return;
+
+    RGBA32* dst = m_target->scanline(rect.top()) + rect.left();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    for (int i = rect.height() - 1; i >= 0; --i) {
+        for (int j = 0; j < rect.width(); ++j)
+            set_pixel_with_draw_op(dst[j], color);
+        dst += dst_skip;
+    }
+}
+
+void Painter::fill_rect(const Rect& a_rect, Color color)
+{
+    if (draw_op() != DrawOp::Copy) {
+        fill_rect_with_draw_op(a_rect, color);
+        return;
+    }
+
+    auto rect = a_rect.translated(translation()).intersected(clip_rect());
+    if (rect.is_empty())
+        return;
+
+    ASSERT(m_target->rect().contains(rect));
+
+    RGBA32* dst = m_target->scanline(rect.top()) + rect.left();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    for (int i = rect.height() - 1; i >= 0; --i) {
+        fast_u32_fill(dst, color.value(), rect.width());
+        dst += dst_skip;
+    }
+}
+
+void Painter::fill_rect_with_gradient(const Rect& a_rect, Color gradient_start, Color gradient_end)
+{
+#ifdef NO_FPU
+    return fill_rect(a_rect, gradient_start);
+#endif
+    auto rect = a_rect.translated(translation());
+    auto clipped_rect = Rect::intersection(rect, clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+
+    int x_offset = clipped_rect.x() - rect.x();
+
+    RGBA32* dst = m_target->scanline(clipped_rect.top()) + clipped_rect.left();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    float increment = (1.0 / ((rect.width()) / 255.0));
+
+    int r2 = gradient_start.red();
+    int g2 = gradient_start.green();
+    int b2 = gradient_start.blue();
+    int r1 = gradient_end.red();
+    int g1 = gradient_end.green();
+    int b1 = gradient_end.blue();
+
+    for (int i = clipped_rect.height() - 1; i >= 0; --i) {
+        float c = x_offset * increment;
+        for (int j = 0; j < clipped_rect.width(); ++j) {
+            dst[j] = Color(
+                r1 / 255.0 * c + r2 / 255.0 * (255 - c),
+                g1 / 255.0 * c + g2 / 255.0 * (255 - c),
+                b1 / 255.0 * c + b2 / 255.0 * (255 - c))
+                         .value();
+            c += increment;
+        }
+        dst += dst_skip;
+    }
+}
+
+void Painter::draw_rect(const Rect& a_rect, Color color, bool rough)
+{
+    Rect rect = a_rect.translated(translation());
+    auto clipped_rect = rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+
+    int min_y = clipped_rect.top();
+    int max_y = clipped_rect.bottom();
+
+    if (rect.top() >= clipped_rect.top() && rect.top() <= clipped_rect.bottom()) {
+        int start_x = rough ? max(rect.x() + 1, clipped_rect.x()) : clipped_rect.x();
+        int width = rough ? min(rect.width() - 2, clipped_rect.width()) : clipped_rect.width();
+        fast_u32_fill(m_target->scanline(rect.top()) + start_x, color.value(), width);
+        ++min_y;
+    }
+    if (rect.bottom() >= clipped_rect.top() && rect.bottom() <= clipped_rect.bottom()) {
+        int start_x = rough ? max(rect.x() + 1, clipped_rect.x()) : clipped_rect.x();
+        int width = rough ? min(rect.width() - 2, clipped_rect.width()) : clipped_rect.width();
+        fast_u32_fill(m_target->scanline(rect.bottom()) + start_x, color.value(), width);
+        --max_y;
+    }
+
+    bool draw_left_side = rect.left() >= clipped_rect.left();
+    bool draw_right_side = rect.right() == clipped_rect.right();
+
+    if (draw_left_side && draw_right_side) {
+        // Specialized loop when drawing both sides.
+        for (int y = min_y; y <= max_y; ++y) {
+            auto* bits = m_target->scanline(y);
+            bits[rect.left()] = color.value();
+            bits[rect.right()] = color.value();
+        }
+    } else {
+        for (int y = min_y; y <= max_y; ++y) {
+            auto* bits = m_target->scanline(y);
+            if (draw_left_side)
+                bits[rect.left()] = color.value();
+            if (draw_right_side)
+                bits[rect.right()] = color.value();
+        }
+    }
+}
+
+void Painter::draw_bitmap(const Point& p, const CharacterBitmap& bitmap, Color color)
+{
+    auto rect = Rect(p, bitmap.size()).translated(translation());
+    auto clipped_rect = rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - rect.top();
+    const int last_row = clipped_rect.bottom() - rect.top();
+    const int first_column = clipped_rect.left() - rect.left();
+    const int last_column = clipped_rect.right() - rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const char* bitmap_row = &bitmap.bits()[first_row * bitmap.width() + first_column];
+    const size_t bitmap_skip = bitmap.width();
+
+    for (int row = first_row; row <= last_row; ++row) {
+        for (int j = 0; j <= (last_column - first_column); ++j) {
+            char fc = bitmap_row[j];
+            if (fc == '#')
+                dst[j] = color.value();
+        }
+        bitmap_row += bitmap_skip;
+        dst += dst_skip;
+    }
+}
+
+void Painter::draw_bitmap(const Point& p, const GlyphBitmap& bitmap, Color color)
+{
+    auto dst_rect = Rect(p, bitmap.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - dst_rect.top();
+    const int last_row = clipped_rect.bottom() - dst_rect.top();
+    const int first_column = clipped_rect.left() - dst_rect.left();
+    const int last_column = clipped_rect.right() - dst_rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    for (int row = first_row; row <= last_row; ++row) {
+        for (int j = 0; j <= (last_column - first_column); ++j) {
+            if (bitmap.bit_at(j + first_column, row))
+                dst[j] = color.value();
+        }
+        dst += dst_skip;
+    }
+}
+
+void Painter::blit_scaled(const Rect& dst_rect_raw, const GraphicsBitmap& source, const Rect& src_rect, float hscale, float vscale)
+{
+    auto dst_rect = Rect(dst_rect_raw.location(), dst_rect_raw.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = (clipped_rect.top() - dst_rect.top());
+    const int last_row = (clipped_rect.bottom() - dst_rect.top());
+    const int first_column = (clipped_rect.left() - dst_rect.left());
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    int x_start = first_column + src_rect.left();
+    for (int row = first_row; row <= last_row; ++row) {
+        int sr = (row + src_rect.top()) * vscale;
+        if (sr >= source.size().height() || sr < 0) {
+            dst += dst_skip;
+            continue;
+        }
+        const RGBA32* sl = source.scanline(sr);
+        for (int x = x_start; x < clipped_rect.width() + x_start; ++x) {
+            int sx = x * hscale;
+            if (sx < source.size().width() && sx >= 0)
+                dst[x - x_start] = sl[sx];
+        }
+        dst += dst_skip;
+    }
+    return;
+}
+
+void Painter::blit_with_opacity(const Point& position, const GraphicsBitmap& source, const Rect& src_rect, float opacity)
+{
+    ASSERT(!m_target->has_alpha_channel());
+
+    if (!opacity)
+        return;
+    if (opacity >= 1.0f)
+        return blit(position, source, src_rect);
+
+    u8 alpha = 255 * opacity;
+
+    Rect safe_src_rect = Rect::intersection(src_rect, source.rect());
+    Rect dst_rect(position, safe_src_rect.size());
+    dst_rect.move_by(state().translation);
+    auto clipped_rect = Rect::intersection(dst_rect, clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - dst_rect.top();
+    const int last_row = clipped_rect.bottom() - dst_rect.top();
+    const int first_column = clipped_rect.left() - dst_rect.left();
+    const int last_column = clipped_rect.right() - dst_rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const unsigned src_skip = source.pitch() / sizeof(RGBA32);
+
+    for (int row = first_row; row <= last_row; ++row) {
+        for (int x = 0; x <= (last_column - first_column); ++x) {
+            Color src_color_with_alpha = Color::from_rgb(src[x]);
+            src_color_with_alpha.set_alpha(alpha);
+            Color dst_color = Color::from_rgb(dst[x]);
+            dst[x] = dst_color.blend(src_color_with_alpha).value();
+        }
+        dst += dst_skip;
+        src += src_skip;
+    }
+}
+
+void Painter::blit_dimmed(const Point& position, const GraphicsBitmap& source, const Rect& src_rect)
+{
+    Rect safe_src_rect = src_rect.intersected(source.rect());
+    auto dst_rect = Rect(position, safe_src_rect.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - dst_rect.top();
+    const int last_row = clipped_rect.bottom() - dst_rect.top();
+    const int first_column = clipped_rect.left() - dst_rect.left();
+    const int last_column = clipped_rect.right() - dst_rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const size_t src_skip = source.pitch() / sizeof(RGBA32);
+
+    for (int row = first_row; row <= last_row; ++row) {
+        for (int x = 0; x <= (last_column - first_column); ++x) {
+            u8 alpha = Color::from_rgba(src[x]).alpha();
+            if (alpha == 0xff)
+                dst[x] = Color::from_rgba(src[x]).to_grayscale().lightened().value();
+            else if (!alpha)
+                continue;
+            else
+                dst[x] = Color::from_rgba(dst[x]).blend(Color::from_rgba(src[x]).to_grayscale().lightened()).value();
+        }
+        dst += dst_skip;
+        src += src_skip;
+    }
+}
+
+void Painter::blit_tiled(const Point& position, const GraphicsBitmap& source, const Rect& src_rect)
+{
+    auto dst_rect = Rect(position, src_rect.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = (clipped_rect.top() - dst_rect.top());
+    const int last_row = (clipped_rect.bottom() - dst_rect.top());
+    const int first_column = (clipped_rect.left() - dst_rect.left());
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    if (source.format() == GraphicsBitmap::Format::RGB32 || source.format() == GraphicsBitmap::Format::RGBA32) {
+        int x_start = first_column + src_rect.left();
+        for (int row = first_row; row <= last_row; ++row) {
+            const RGBA32* sl = source.scanline((row + src_rect.top())
+                % source.size().height());
+            for (int x = x_start; x < clipped_rect.width() + x_start; ++x) {
+                dst[x - x_start] = sl[x % source.size().width()];
+            }
+            dst += dst_skip;
+        }
+        return;
+    }
+
+    ASSERT_NOT_REACHED();
+}
+
+void Painter::blit_offset(const Point& position,
+    const GraphicsBitmap& source,
+    const Rect& src_rect,
+    const Point& offset)
+{
+    auto dst_rect = Rect(position, src_rect.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = (clipped_rect.top() - dst_rect.top());
+    const int last_row = (clipped_rect.bottom() - dst_rect.top());
+    const int first_column = (clipped_rect.left() - dst_rect.left());
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    if (source.format() == GraphicsBitmap::Format::RGB32 || source.format() == GraphicsBitmap::Format::RGBA32) {
+        int x_start = first_column + src_rect.left();
+        for (int row = first_row; row <= last_row; ++row) {
+            int sr = row - offset.y() + src_rect.top();
+            if (sr >= source.size().height() || sr < 0) {
+                dst += dst_skip;
+                continue;
+            }
+            const RGBA32* sl = source.scanline(sr);
+            for (int x = x_start; x < clipped_rect.width() + x_start; ++x) {
+                int sx = x - offset.x();
+                if (sx < source.size().width() && sx >= 0)
+                    dst[x - x_start] = sl[sx];
+            }
+            dst += dst_skip;
+        }
+        return;
+    }
+
+    ASSERT_NOT_REACHED();
+}
+
+void Painter::blit_with_alpha(const Point& position, const GraphicsBitmap& source, const Rect& src_rect)
+{
+    ASSERT(source.has_alpha_channel());
+    Rect safe_src_rect = src_rect.intersected(source.rect());
+    auto dst_rect = Rect(position, safe_src_rect.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - dst_rect.top();
+    const int last_row = clipped_rect.bottom() - dst_rect.top();
+    const int first_column = clipped_rect.left() - dst_rect.left();
+    const int last_column = clipped_rect.right() - dst_rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+    const size_t src_skip = source.pitch() / sizeof(RGBA32);
+
+    for (int row = first_row; row <= last_row; ++row) {
+        for (int x = 0; x <= (last_column - first_column); ++x) {
+            u8 alpha = Color::from_rgba(src[x]).alpha();
+            if (alpha == 0xff)
+                dst[x] = src[x];
+            else if (!alpha)
+                continue;
+            else
+                dst[x] = Color::from_rgba(dst[x]).blend(Color::from_rgba(src[x])).value();
+        }
+        dst += dst_skip;
+        src += src_skip;
+    }
+}
+
+void Painter::blit(const Point& position, const GraphicsBitmap& source, const Rect& src_rect, float opacity)
+{
+    if (opacity < 1.0f)
+        return blit_with_opacity(position, source, src_rect, opacity);
+    if (source.has_alpha_channel())
+        return blit_with_alpha(position, source, src_rect);
+    auto safe_src_rect = src_rect.intersected(source.rect());
+    ASSERT(source.rect().contains(safe_src_rect));
+    auto dst_rect = Rect(position, safe_src_rect.size()).translated(translation());
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+    const int first_row = clipped_rect.top() - dst_rect.top();
+    const int last_row = clipped_rect.bottom() - dst_rect.top();
+    const int first_column = clipped_rect.left() - dst_rect.left();
+    RGBA32* dst = m_target->scanline(clipped_rect.y()) + clipped_rect.x();
+    const size_t dst_skip = m_target->pitch() / sizeof(RGBA32);
+
+    if (source.format() == GraphicsBitmap::Format::RGB32 || source.format() == GraphicsBitmap::Format::RGBA32) {
+        const RGBA32* src = source.scanline(src_rect.top() + first_row) + src_rect.left() + first_column;
+        const size_t src_skip = source.pitch() / sizeof(RGBA32);
+        for (int row = first_row; row <= last_row; ++row) {
+            fast_u32_copy(dst, src, clipped_rect.width());
+            dst += dst_skip;
+            src += src_skip;
+        }
+        return;
+    }
+
+    if (source.format() == GraphicsBitmap::Format::Indexed8) {
+        const u8* src = source.bits(src_rect.top() + first_row) + src_rect.left() + first_column;
+        const size_t src_skip = source.pitch();
+        for (int row = first_row; row <= last_row; ++row) {
+            for (int i = 0; i < clipped_rect.width(); ++i)
+                dst[i] = source.palette_color(src[i]).value();
+            dst += dst_skip;
+            src += src_skip;
+        }
+        return;
+    }
+
+    ASSERT_NOT_REACHED();
+}
+
+template<bool has_alpha_channel, typename GetPixel>
+ALWAYS_INLINE static void do_draw_integer_scaled_bitmap(GraphicsBitmap& target, const Rect& dst_rect, const GraphicsBitmap& source, int hfactor, int vfactor, GetPixel get_pixel)
+{
+    for (int y = source.rect().top(); y <= source.rect().bottom(); ++y) {
+        int dst_y = dst_rect.y() + y * vfactor;
+        for (int x = source.rect().left(); x <= source.rect().right(); ++x) {
+            auto src_pixel = get_pixel(source, x, y);
+            for (int yo = 0; yo < vfactor; ++yo) {
+                auto* scanline = (Color*)target.scanline(dst_y + yo);
+                int dst_x = dst_rect.x() + x * hfactor;
+                for (int xo = 0; xo < hfactor; ++xo) {
+                    if constexpr (has_alpha_channel)
+                        scanline[dst_x + xo] = scanline[dst_x + xo].blend(src_pixel);
+                    else
+                        scanline[dst_x + xo] = src_pixel;
+                }
+            }
+        }
+    }
+}
+
+template<bool has_alpha_channel, typename GetPixel>
+ALWAYS_INLINE static void do_draw_scaled_bitmap(GraphicsBitmap& target, const Rect& dst_rect, const Rect& clipped_rect, const GraphicsBitmap& source, const Rect& src_rect, int hscale, int vscale, GetPixel get_pixel)
+{
+    if (dst_rect == clipped_rect && !(dst_rect.width() % src_rect.width()) && !(dst_rect.height() % src_rect.height())) {
+        int hfactor = dst_rect.width() / src_rect.width();
+        int vfactor = dst_rect.height() / src_rect.height();
+        if (hfactor == 2 && vfactor == 2)
+            return do_draw_integer_scaled_bitmap<has_alpha_channel>(target, dst_rect, source, 2, 2, get_pixel);
+        if (hfactor == 3 && vfactor == 3)
+            return do_draw_integer_scaled_bitmap<has_alpha_channel>(target, dst_rect, source, 3, 3, get_pixel);
+        if (hfactor == 4 && vfactor == 4)
+            return do_draw_integer_scaled_bitmap<has_alpha_channel>(target, dst_rect, source, 4, 4, get_pixel);
+        return do_draw_integer_scaled_bitmap<has_alpha_channel>(target, dst_rect, source, hfactor, vfactor, get_pixel);
+    }
+
+    for (int y = clipped_rect.top(); y <= clipped_rect.bottom(); ++y) {
+        auto* scanline = (Color*)target.scanline(y);
+        for (int x = clipped_rect.left(); x <= clipped_rect.right(); ++x) {
+            auto scaled_x = ((x - dst_rect.x()) * hscale) >> 16;
+            auto scaled_y = ((y - dst_rect.y()) * vscale) >> 16;
+            auto src_pixel = get_pixel(source, scaled_x, scaled_y);
+
+            if constexpr (has_alpha_channel) {
+                scanline[x] = scanline[x].blend(src_pixel);
+            } else
+                scanline[x] = src_pixel;
+        }
+    }
+}
+
+void Painter::draw_scaled_bitmap(const Rect& a_dst_rect, const GraphicsBitmap& source, const Rect& src_rect)
+{
+    auto dst_rect = a_dst_rect;
+    if (dst_rect.size() == src_rect.size())
+        return blit(dst_rect.location(), source, src_rect);
+
+    auto safe_src_rect = src_rect.intersected(source.rect());
+    ASSERT(source.rect().contains(safe_src_rect));
+    dst_rect.move_by(state().translation);
+    auto clipped_rect = dst_rect.intersected(clip_rect());
+    if (clipped_rect.is_empty())
+        return;
+
+    int hscale = (src_rect.width() << 16) / dst_rect.width();
+    int vscale = (src_rect.height() << 16) / dst_rect.height();
+
+    if (source.has_alpha_channel()) {
+        switch (source.format()) {
+        case GraphicsBitmap::Format::RGB32:
+            do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>);
+            break;
+        case GraphicsBitmap::Format::RGBA32:
+            do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>);
+            break;
+        case GraphicsBitmap::Format::Indexed8:
+            do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::Indexed8>);
+            break;
+        default:
+            do_draw_scaled_bitmap<true>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::Invalid>);
+            break;
+        }
+    } else {
+        switch (source.format()) {
+        case GraphicsBitmap::Format::RGB32:
+            do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>);
+            break;
+        case GraphicsBitmap::Format::RGBA32:
+            do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::RGB32>);
+            break;
+        case GraphicsBitmap::Format::Indexed8:
+            do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::Indexed8>);
+            break;
+        default:
+            do_draw_scaled_bitmap<false>(*m_target, dst_rect, clipped_rect, source, src_rect, hscale, vscale, get_pixel<GraphicsBitmap::Format::Invalid>);
+            break;
+        }
+    }
+}
+
+[[gnu::flatten]] void Painter::draw_glyph(const Point& point, char ch, Color color)
+{
+    draw_glyph(point, ch, font(), color);
+}
+
+[[gnu::flatten]] void Painter::draw_glyph(const Point& point, char ch, const Font& font, Color color)
+{
+    draw_bitmap(point, font.glyph_bitmap(ch), color);
+}
+
+void Painter::draw_text_line(const Rect& a_rect, const StringView& text, const Font& font, TextAlignment alignment, Color color, TextElision elision)
+{
+    auto rect = a_rect;
+    StringView final_text(text);
+    String elided_text;
+    if (elision == TextElision::Right) {
+        int text_width = font.width(final_text);
+        if (font.width(final_text) > rect.width()) {
+            int glyph_spacing = font.glyph_spacing();
+            int new_length = 0;
+            int new_width = font.width("...");
+            if (new_width < text_width) {
+                for (int i = 0; i < final_text.length(); ++i) {
+                    int glyph_width = font.glyph_width(final_text.characters_without_null_termination()[i]);
+                    // NOTE: Glyph spacing should not be added after the last glyph on the line,
+                    //       but since we are here because the last glyph does not actually fit on the line,
+                    //       we don't have to worry about spacing.
+                    int width_with_this_glyph_included = new_width + glyph_width + glyph_spacing;
+                    if (width_with_this_glyph_included > rect.width())
+                        break;
+                    ++new_length;
+                    new_width += glyph_width + glyph_spacing;
+                }
+                StringBuilder builder;
+                builder.append(StringView(final_text.characters_without_null_termination(), new_length));
+                builder.append("...");
+                elided_text = builder.to_string();
+                final_text = elided_text;
+            }
+        }
+    }
+
+    if (alignment == TextAlignment::TopLeft) {
+        // No-op.
+    } else if (alignment == TextAlignment::CenterLeft) {
+        // No-op.
+    } else if (alignment == TextAlignment::CenterRight) {
+        rect.set_x(rect.right() - font.width(final_text));
+    } else if (alignment == TextAlignment::Center) {
+        auto shrunken_rect = rect;
+        shrunken_rect.set_width(font.width(final_text));
+        shrunken_rect.center_within(rect);
+        rect = shrunken_rect;
+    } else {
+        ASSERT_NOT_REACHED();
+    }
+
+    auto point = rect.location();
+    int space_width = font.glyph_width(' ') + font.glyph_spacing();
+
+    for (ssize_t i = 0; i < final_text.length(); ++i) {
+        char ch = final_text.characters_without_null_termination()[i];
+        if (ch == ' ') {
+            point.move_by(space_width, 0);
+            continue;
+        }
+        draw_glyph(point, ch, font, color);
+        point.move_by(font.glyph_width(ch) + font.glyph_spacing(), 0);
+    }
+}
+
+void Painter::draw_text(const Rect& rect, const StringView& text, TextAlignment alignment, Color color, TextElision elision)
+{
+    draw_text(rect, text, font(), alignment, color, elision);
+}
+
+void Painter::draw_text(const Rect& rect, const StringView& text, const Font& font, TextAlignment alignment, Color color, TextElision elision)
+{
+    Vector<StringView, 32> lines;
+
+    int start_of_current_line = 0;
+    for (int i = 0; i < text.length(); ++i) {
+        auto ch = text[i];
+        if (ch == '\n') {
+            lines.append(text.substring_view(start_of_current_line, i - start_of_current_line));
+            start_of_current_line = i + 1;
+            continue;
+        }
+    }
+
+    if (start_of_current_line != text.length()) {
+        lines.append(text.substring_view(start_of_current_line, text.length() - start_of_current_line));
+    }
+
+    static const int line_spacing = 4;
+    int line_height = font.glyph_height() + line_spacing;
+    Rect bounding_rect { 0, 0, 0, (lines.size() * line_height) - line_spacing };
+
+    for (auto& line : lines) {
+        auto line_width = font.width(line);
+        if (line_width > bounding_rect.width())
+            bounding_rect.set_width(line_width);
+    }
+
+    if (alignment == TextAlignment::TopLeft) {
+        bounding_rect.set_location(rect.location());
+    } else if (alignment == TextAlignment::CenterLeft) {
+        bounding_rect.set_location({ rect.x(), rect.center().y() - (bounding_rect.height() / 2) });
+    } else if (alignment == TextAlignment::CenterRight) {
+        bounding_rect.set_location({ rect.right() - bounding_rect.width(), rect.center().y() - (bounding_rect.height() / 2) });
+    } else if (alignment == TextAlignment::Center) {
+        bounding_rect.center_within(rect);
+    } else {
+        ASSERT_NOT_REACHED();
+    }
+
+    for (int i = 0; i < lines.size(); ++i) {
+        auto& line = lines[i];
+        Rect line_rect { bounding_rect.x(), bounding_rect.y() + i * line_height, bounding_rect.width(), line_height };
+        line_rect.intersect(rect);
+        draw_text_line(line_rect, line, font, alignment, color, elision);
+    }
+}
+
+void Painter::set_pixel(const Point& p, Color color)
+{
+    auto point = p;
+    point.move_by(state().translation);
+    if (!clip_rect().contains(point))
+        return;
+    m_target->scanline(point.y())[point.x()] = color.value();
+}
+
+[[gnu::always_inline]] inline void Painter::set_pixel_with_draw_op(u32& pixel, const Color& color)
+{
+    if (draw_op() == DrawOp::Copy)
+        pixel = color.value();
+    else if (draw_op() == DrawOp::Xor)
+        pixel ^= color.value();
+}
+
+void Painter::draw_pixel(const Point& position, Color color, int thickness)
+{
+    ASSERT(draw_op() == DrawOp::Copy);
+    if (thickness == 1)
+        return set_pixel_with_draw_op(m_target->scanline(position.y())[position.x()], color);
+    Rect rect { position.translated(-(thickness / 2), -(thickness / 2)), { thickness, thickness } };
+    fill_rect(rect, color);
+}
+
+void Painter::draw_line(const Point& p1, const Point& p2, Color color, int thickness)
+{
+    auto clip_rect = this->clip_rect();
+
+    auto point1 = p1;
+    point1.move_by(state().translation);
+
+    auto point2 = p2;
+    point2.move_by(state().translation);
+
+    // Special case: vertical line.
+    if (point1.x() == point2.x()) {
+        const int x = point1.x();
+        if (x < clip_rect.left() || x > clip_rect.right())
+            return;
+        if (point1.y() > point2.y())
+            swap(point1, point2);
+        if (point1.y() > clip_rect.bottom())
+            return;
+        if (point2.y() < clip_rect.top())
+            return;
+        int min_y = max(point1.y(), clip_rect.top());
+        int max_y = min(point2.y(), clip_rect.bottom());
+        for (int y = min_y; y <= max_y; ++y)
+            draw_pixel({ x, y }, color, thickness);
+        return;
+    }
+
+    // Special case: horizontal line.
+    if (point1.y() == point2.y()) {
+        const int y = point1.y();
+        if (y < clip_rect.top() || y > clip_rect.bottom())
+            return;
+        if (point1.x() > point2.x())
+            swap(point1, point2);
+        if (point1.x() > clip_rect.right())
+            return;
+        if (point2.x() < clip_rect.left())
+            return;
+        int min_x = max(point1.x(), clip_rect.left());
+        int max_x = min(point2.x(), clip_rect.right());
+        for (int x = min_x; x <= max_x; ++x)
+            draw_pixel({ x, y }, color, thickness);
+        return;
+    }
+
+    const double adx = abs(point2.x() - point1.x());
+    const double ady = abs(point2.y() - point1.y());
+
+    if (adx > ady) {
+        if (point1.x() > point2.x())
+            swap(point1, point2);
+    } else {
+        if (point1.y() > point2.y())
+            swap(point1, point2);
+    }
+
+    // FIXME: Implement clipping below.
+    const double dx = point2.x() - point1.x();
+    const double dy = point2.y() - point1.y();
+    double error = 0;
+
+    if (dx > dy) {
+        const double y_step = dy == 0 ? 0 : (dy > 0 ? 1 : -1);
+        const double delta_error = fabs(dy / dx);
+        int y = point1.y();
+        for (int x = point1.x(); x <= point2.x(); ++x) {
+            if (clip_rect.contains(x, y))
+                draw_pixel({ x, y }, color, thickness);
+            error += delta_error;
+            if (error >= 0.5) {
+                y = (double)y + y_step;
+                error -= 1.0;
+            }
+        }
+    } else {
+        const double x_step = dx == 0 ? 0 : (dx > 0 ? 1 : -1);
+        const double delta_error = fabs(dx / dy);
+        int x = point1.x();
+        for (int y = point1.y(); y <= point2.y(); ++y) {
+            if (clip_rect.contains(x, y))
+                draw_pixel({ x, y }, color, thickness);
+            error += delta_error;
+            if (error >= 0.5) {
+                x = (double)x + x_step;
+                error -= 1.0;
+            }
+        }
+    }
+}
+
+void Painter::add_clip_rect(const Rect& rect)
+{
+    state().clip_rect.intersect(rect.translated(m_clip_origin.location()));
+    state().clip_rect.intersect(m_target->rect());
+}
+
+void Painter::clear_clip_rect()
+{
+    state().clip_rect = m_clip_origin;
+}
+
+PainterStateSaver::PainterStateSaver(Painter& painter)
+    : m_painter(painter)
+{
+    m_painter.save();
+}
+
+PainterStateSaver::~PainterStateSaver()
+{
+    m_painter.restore();
+}